I like Markor. https://f-droid.org/packages/net.gsantner.markor/

Quillpad meets all your requirements. It's a great notes app

Markor is, by far, the best.

They did start accepting AI-generated contributions a while ago, but the latest release (2.16.1) is still clean.

In addition to Markdown docs and to-dos, it also supports Org-Mode, AsciiDoc, ZimWiki, todo.txt, and (of course) plaintext.

However, it does not have a tiled view.

For me the golden standard for "simple" are Fossify and SecUSo. You can find all their apps on F-Droid.

I haven't tried their specific apps for notes, so I'm not sure about the bullet points 2 and 3 but maybe they are worth a try.

Markor makes you pick a title before you can type and the quick notes feature doesn't quite ameliorate the issue for me so I specifically went looking for the same and found one called Markleaf on F Droid that does what I want. It has a nice tagging feature.

Simple Notes Sync is pretty good

I personally use Easy Notes

Does Joplin really take a long time to start up compared to the rest? I just got it downloaded and synced with my server yesterday and so far it opens up almost instantly every time.

Markor is pretty neat.

Obsidian supports markdown, but it isn't foss -- but it doesn't lock you in either

I use Logseq for this, but it's probably a bit heavy for you. I sync it via git with other devices.