mr_right

Security is not as huge of a problem on linux as it is on windows for sure. But EVERY SINGLE proprietary app you use can snoop on EVERYTHING. and I do not trust proprietary apps, beginners especially will use a ton of proprietary software. Remember that we're recommending to a beginner, not a linux evangelist who is willing to do anything to make linux/foss work for them.

i don't trust them either but from what i have seen most don't care

The only reason I see for a beginner not to choose KDE over xfce is if they have a laptop from the 32 bit era.

this is a bit of a stretch

the development rate is a deciding factor for sure and i agree that we shouldn't encourage using software that is considered "obsolete"

i don't agree on everything and maybe you're right i still don't get why they dropped support for kde but still support MATE

first this is not a criticism of kde. use what ever you want i just want to keep expectations within the realm of reality.

now about the security issues, afaik those problems exists because X11 not cinnamon specifically which is why cinnamon for Wayland exists ( it's gonna take WAY longer to mature than KDE), but i don't think that this is a big problem for most for now since our user base is small so there is much less malware and targeted attacks (well as long as you are not a high profile employee at a company with vast data access privileges )

the mixed dpi displays is a fair point too, i do that sometimes and i would say that i used it more than the people i know who might used it once or twice for a PowerPoint representation or something. programmers, gamers, graphical designers are peanuts compared to office work and regular users ( watching youtube, arguing on the internet etc)

i don't understand what you mean exactly by performance when talking about a DE ( responsiveness, ram and cpu usage ? ...). in terms of cpu and ram usage i'm pretty sure that kde consumes more and in terms responsiveness i would assume that kde is better but how much ( a difference between 5 s and 2 s is huge but from let's say 80 nanosecond to 60 is just for benchmarks and won't be noticed in real world usage)

what really holds us back is the lack of commercial software compatibility and at least decent alternatives compared to industry standards

oh yeah, and nvidia drivers + wifi and bluetouth

i agree that immutable distros are good for beginners and this is especially true for users who are not exactly tech savvy or don't want to mess with their systems, but i don't think the features that cinnamon misses are that important to as many users as you think there are

HDR is nice but not everyone can afford it, and mixed refresh rate displays might be important for gamers and desktop users but not as much in a laptop ( and yes i know that high refresh rates drain the battery but why would you game on battery anyway ), mixed DPI displays ??? only a small subset of users have those. yes the OP is a heavy multitasker but again he is using a laptop (but having support is nice)

however what i do agree with is that fractional scaling is awful in cinnamon and the reason i consider it a serious problem is that high res displays are now common and fractional scaling directly affects user experience

Yep

flatpak install/update <package name> --no-related

there problem solved