Age of Empires 4 is not the same as Age of Empires Online and is a a full fledged game in the Age of Empires Series incredibly similar to AOE2 with some learnings from AOE3 added in.[1] It very much plays like it’s predecessors. It is highly enjoyable and has a very active community as responsive developers. There are many content creators and tournaments for this game now. It has a large enough userbase for you to be able to find a game quickly and they are constantly releasing new content and patches. The latest patch was released quite recently.[2]
AOE2, 3 and 4 have lots of tournaments, some of them with quite decent prize pools.[3]
I personally don’t play AOM so I can’t comment on that but as far as I have seen, Microsoft has done a good job at reviving the other games and with the new game so while I don’t doubt AOM is buggy I do have faith they are actively attempting to fix issues.
As for the Windows only thing, as I said, I use windows at times myself and I don’t mind paying for proprietary software. But I understand if others have qualms about that.
But to say that the Age of Empires series died with AOE3 is untrue, and while 0AD is a great achievement, to say it is a replacement for the actual Age games is also not true.
Also note that MS did reimplement the engine for the AOEI definitive edition, unsure about the others.
1 https://en.wikipedia.org/wiki/Age_of_Empires_IV
2 https://www.ageofempires.com/news/age-of-empires-iv-season-f...
3 https://liquipedia.net/ageofempires/Main_Page