These rumors/stories, whatever you want to call them, is all new to me, but its just a way to dehumanize a certain group and therefore helping to justify labelling them the new boogieman.
ELI5 Its a way to make a group of people appear less human and different from yourself. This makes it easier to not relate to them and use them as a bad/ evil example of something you want to avoid.
I think you are confusing private with anonymous. One can be private without being anonymous.
Its due to compression of the video in order to fit on a MMS message, which is very small. Android uses RCS as a new message standard that can send bigger files but Apple has yet to add it to their OS. Its similar to how Apple uses iMessage to do the same, however this is not a standard and is locked to only apple devices.
Apple is supposedly adding support for RCS during the new iOS update but until then you can use a different messaging app to send better/larger files.
I recommend Signal as it is easy to sign up and start using while also being private.
You should be fine doing what you want on Linux. Just make sure everything works before installing completely. There is a liveUSB mode that let's you try it before you install.
Mint and PoP os are good ones to try.
Can also check out Zorin os which is pretty good too but doesn't update as often.
Isn't matrix more like slack that you are looking for?
Without much context all I can suggest is PowerAmp for music player. It is a paid app.
Eternity for Lemmy.
Heliboard for a more private keyboard.
Newpipe for YouTube.
Fallout - Tale of two wastelands.....hopefully that counts as one game, if not then Skyrim. For the endless mods.
Hades or Binding of Issac - for the infinite replayability.
Minecraft - for the creative aspect of building and lots of content.
Straight chilled water.
If I need extra hydration aka eletrolytes, I either put pure electrolytes in it or a flavored powder like Liquid IV.
Desktops. Don't have to worry about batteries and easier to swap out parts.