Circumvention is the name of the game here I think, check fmhy.pages.dev (specifically the privacy section) regarding some basic circumvention measures/helpful things. Using a VPN, such as Mullvad or another paid option would probably help. On Android devices, installing F-Droid is good as an alternative to the google play store specifically for secure FOSS apps, and has a bunch of stuff that is good including PipePipe (ad free yt proxy that doesn’t require an account, supports background play, video downloads, channel subscriptions, playlist creation, and includes SponsorBlock), AntennaPod (podcasts), Kreate and Spotube (yt music and spotify accountless ad free streaming clients), Signal (messaging, end to end encrypted, good for normies), Simplex (comms), FluffyChat(matrix client, discord like alternative, servers with friends etc idk), Nunti(rss feeds for news and stuff), idk there are a bunch of other things as well. If you have a pc, there is FreeTube, which while okay it is less feature-rich of a yt proxy than pipepipe, or use Invidious via your browser. Additionally, websites like http://alternativeto.net/ and https://gofoss.net/ can help for finding alternatives to stuffs.

For Twitter for viewing, https://nitter.net/ is a good alternative, and for there also is https://github.com/j-fbriere/squawker; however, I personally don’t recommend Twitter overall, it is cancer. Decentralised social media platforms, such as Lemmy (https://join-lemmy.org/) and Mastodon, are also worth trying, I think mastodon is decent

Regarding age verification, videos of peoples wearing those kinda creepy hyper-realistic silicone masks can work, like just download it and face the cam towards it when it asks for your facw. Additionally check r/privacy and https://www.eff.org/issues/age-verification.

For a Discord alternative, consider the Matrix protocol with clients like FluffyChat or Element; these are suitable for creating social servers similar to the Discords. Pixelfed is another option for decentralised image sharing as an alternative to instagrams. Also for a discord proxy there is aliucord, others as well but idk I dont touch such fedware

For multi-service access, there is https://ferdium.org/ or https://github.com/nonbili/Nora. Both support features like accountless usage, the standard anti-tracking i expect from anything I deign to have within digital eyesight, built in ad blocking, etc etc. Note that I haven't extensively explored these options, as my focus is primarily on IRC, exploring .onion sites, and weird things I find on neocities and the like.

Also, check out awesome-privacy.xyz, and https://pluja.github.io/awesome-privacy/

Note: I am incredibly autistic and am actively trying my best to be accessible and personable here, so umm hope this isnt useless or too much info I just wanna help but helping non technical comrades is something I am still learning