beep boop

The mission can be seen in full here, though obviously you should consider carefully before clicking.
Or what? I might see pixels from a video game.
https://xcancel.com/GTASixInfo/status/2010798891269243103
Except for the mission name and general concept of “roof, gun, tent, crowd” its quite the shit recreation honestly.

Its good training for arguing with real life people at least. Because coming up with a good comeback quickly is hard when you have never formulated your thoughts about a subject properly. I think often people misunderstand things at first and then when someone points out their mistake, they realize that they were wrong, but dont want to admit it, so they just double down. I have been that person before too tho…

signal only knows a phone number in association with an account creation date and the last sent message date. everything else is encrypted.
Thats not really possible. If thats all they give out, then that just means that is all that they decide to save. They have access to the servers that everyones messages pass through. They could log the IP and date for every single message sent if they wanted to, but just decide not to do it. This model fails however as soon as they are forced to save more than that.

only add people to your group chats that you have good reason to trust
Yeah people need to really set trust hierarchies for this kinda political organizing. Sort of a “Principle of least privilege” but for people.
Only post personal or identifying information in chats where everyone already knows every other person directly. Public or effectively public(with more than like 10 people) chats should never ever have any identifying information in them.
Dont use a SIM card. Which also means dont use Signal unless you have a number than cant be linked to you.
They will absolutely plant long term rats for this shit so if you havent known someone for years, then think twice about telling them things they dont need to know.
If people are actually serious about organizing then tell them to use Briar. There is nothing else that comes close to it. You shouldnt use your primary phone for shit like this anyways so it doesnt matter if they are apple users, they should get a 100$ android just for this.
https://en.wikipedia.org/wiki/Briar_(software)
https://briarproject.org/
I havent used this specific app but ones like it, but this should do what you want.

No. The most played games on steam are multiplayer games that use some sort of anti cheat. Those anti cheats often break linux compatibility when the game or anticheat itself gets updated. So going by number of games you are mostly right, but going by player counts there are often massive setbacks that either dont get fixed at all or only very slowly. Apex Legends and The Finals are prime examples of this flip flopping between working and broken.
You could always run another virtual linux in your linux to make it safer.