I wouldn't want to speak over people who know the game's capabilities better than I do, but I'd be shocked if the game could handle 12 players without massive, unacceptable lag. 8 players is already a challenge in a lot of cases.
If I had to take a big guess as to why the player base might be shrinking right now, I'd say it's this. I know I really ramped up my playing during the pandemic and haven't been as active in the last year+. I think lots of others are in a similar position.
I won't deny the toxic stuff happens. I've seen it. But I'm not convinced it's happening any more often now than it was a few years ago.
If they actually fight, I suspect Zuckerberg's strategy of training for a fight will work out better for him than Musk's strategy of non-stop shitposting on Twitter.
I was able to install the mod on A26, but it didn't work. Every time I try to play against Elytra, no matter the difficulty level, the AI just sits there and doesn't do anything. Its troops just stand around the CC.
Oh my God, the end of boonGUI? End of an era, and a really, really excellent project.
To be honest, I think boonGUI, more than anything, is what has kept the game interesting for me the last several years. Along with watching vids from Tom0ad and NewbieRush, both of which also make extensive use of boonGUI.
I'd probably make a case for more 3v3 play. At its best, 3v3 has all the best features of 4v4 without the lag. 2v2, imo, tends to descend into "parallel 1v1" games.
I seem to remember this issue arising a few other times, mainly the one about it not being present when you expect it to be there. I think the usual problem is that if you happen to make a stray click or give an additional order to some units, the "back to work" button disappears. The button only appears when you go directly from resource-gathering to fighting without giving them additional orders after the fight. Once you've given additional orders after the fight, you no longer get the "back to work" button.
After running the software update to 13.1, I had the same problem and fixed it with the same solution. So, yeah, looks like this might be a general issue with Ventura 13.1.
I don't know the details of your situation. But I currently have OS 13.0.1 Ventura and run 0AD just fine. I haven't yet run the software update to 13.1, though.