Bazzite supports Nvidia graphics cards, which is a major difference if it affects your hardware.

It also uses the same kernal optimizations for gaming that Glorious Eggroll maintains for CachyOS, which I doubt SteamOS utilizes. It's not a huge increase to performance and they slow down write speeds to disk as a tradeoff, but it'll often get you a couple extra frames in games.

Bazzite also uses Bazaar instead of Discovery as its application manager. They're both based on FlatHub, but you might have slight variations in available software.

Nah. Bazzite has been rock solid and have done so much to assist with compatibility with 3rd party hardware. SteamOS is of course great, but steamos is focused on their hardware, because is focused on making it work for everyone.

In other words I ain't lookin to fix what ain't broken

They aren't the same at all. SteamOS is based on Arch and Bazzite on Fedora. They use different versions of software. Bazzite just aims to work the same as SteamOS.

The advantage of Bazzite is that you have more control over your system.

SteamOS is optimised for Valve's hardware, and at present it only officially supports AMD GPUs, and not all of them. They are rolling out support for more AMD hardware, and "working with" Intel and Nvidia to do the same. Support is a big deal, especially as it's an immutable system and it's not got a big ecosystem of users/volunteers managing the packages and providing alternatives. Configuring and modifying it is more difficult than a non immutable system, so you are very dependent on the official options the distro provides to customise your system. It's based off Arch which is completely different to Bazzite. Arch doesn't have it's own immutable versions to work with (there are immutable distros based on Arch, but not ones that SteamOS is based on), so if you need to problem solve you're restricted to SteamOS specific advice, and whatever Valve currently has within it's repos. It's likely 3rd parties will add more options but at present it's a focused distro.

Bazzite meanwhile is an open distro project, which is also immutable but built from the start to support (and tested on) a huge range of gaming PCs and other hardware, including with Nvidia GPUs. There are lots of users & volunteers already involved that are motivated to ensure it works with all the major graphics cards, and keep up to date as they use it themselves. It is also based off Fedora Kinoite, which has an established immutable ecosystem which eases some of the friction when finding support. This also means likely more software within the main Bazzite repos already tailored for the immutable system, alongside the usual options in Flatpaks and AppImages. But Bazzite also includes Waydroid to allow android software use, and is already set up with Homebrew & Distrobox to give more options. It's unlikely SteamOS has these things set up or at least easily set up for users.

With an immutable system it's important to have options to get software installed, although it's possible in a HTPC set up you'll find what you need in the main repos of SteamOS, Flatpaks and AppImages so maybe it won't be an issue.

SteamOS is a great concept and I like it on my Steam Deck, but it's not really something to run on your devices while so early in it's support system. If your device is AMD based then maybe you'll have no issues, but I don't think being an early adopter on a system you want to use daily is a great idea. Maybe you won't need the wide range of software and options Bazzite offers, but Bazzite does offer much more "out of the box" at the moment as a mature and established distro.

Side question:

Bazzite or CachyOS on a new gaming laptop?

No. Frankly I trust the community to maintain my distro more than a trust Valve. Plus Bazzite is generally great and I like the ostree style of atomic Linux.

I haven't checked the update since they have released it wider with the Steam Machine release. But their hardware support is much more limited: heavily focusing on their own hardware. It use to not work at all really outside of Steam Deck. If you have very similar hardware, maybe switch. Otherwise Bazzite is really the way to go. Much wider hardware support, supports Nvidia, and has additional optimizations.

I know Bazzite is the deck build for HTPC, and is in testing right now for the next updates.

Eh... not quite sure what exactly you are trying to say, but:

Bazzite has multiple variants, and they have a webpage that points you at the correct one.

https://bazzite.gg/#image-picker

There is also the FAQ:

https://docs.bazzite.gg/General/FAQ/

What Bazzite image do I use?

Bazzite's website offers a streamlined way of selecting the correct image which will be chosen based on hardware, desktop environment, and to include Steam Gaming Mode if the hardware supports it.

Bazzite offers multiple images, but most images will be following one of these three variants:

Variant 1: Bazzite images that do not have Steam Gaming Mode and receive automatic updates daily with gaming packages pre-installed.

Variant 2: Bazzite images that automatically boot into Steam Gaming Mode (like SteamOS) and are intended for controller-oriented setups.

Variant 3: Bazzite images that are intended for software development.

... anyway, as others have said, there are actually a lot of differences between Bazzite and SteamOS.

Honestly just read all of the FAQ page.

I think that Bazzite is the better OS for general purpose systems. I prefer the newer software (especially Kernel, Mesa and KDE) and I really like the ujust scripts.

Currently on Arch with hyprland, but I'm considering switching to Bazzite or SteamOS. My understanding is SteamOS doesn't support multiple monitor setups well. So that's what gives me pause on trying that.

But end of the day if what you have is working, there's not much reason to switch to one unless you're curious to poke around.

There really isn’t any difference between in Bazzite or SteamOS in my understanding.

This is not true. Not saying one is better than the other here, but they are quite different really - for a start one is a Fedora derivative and the other is an Arch derivative. They are both aiming to fill the same purpose (Handhelds and HTPC), but how they get there is significantly different imo.

For some reason I was under the impression that bazzite was no longer being worked on? Or was that nobara? What am I thinking or or misremembering?

I installed it on my ASUS ROG and it runs brilliantly.

My HTPC runs Fedora Kionite with bigscreen, I just don't see what Bazzite can that I can't do with any other Distro

O am thinking of doing the opposite. I received my steam machine last week and feel it is just a bit to limited. I have been dailying endeavourOS får many years by now and miss the air and yay. I know I can install it on the steamOD, but messing with the immutable nature of it feels wrong.

My biggest Gripe with steamOS out of the box is KDE 6.4. I miss Gnome

Nope, Bazzite is really solid. Also since Steam sells a console with SteamOS they are likely mandated to add in age attestation and whatever else gets ruled necessary.