Friends should help finetune each other's TikTok/Youtube content recommendation algorithms to maximize usefulness and minimize time wasting. Log into each other's accounts and teach each other's algorithms.
Remove nonsense, distractions, and time-wasting content from people's lives while adding more of what people individually should be seeing - content that is useful in getting them to where they want/should be going in life.
If you're going to spend time on TikTok/Youtube, you should at least get the most benefit for your time invested.
Break out of echo chambers and broaden your horizons. By having others influence your feed, you get some diversity into your life.
Friends know each other's problems. Nudge each other's algorithms towards finding solutions.
By helping a friend shift their feed to more useful recommendations, you train yourself to being more mindful of what's happening with yours. Take care of yours as you do for your friends.
A proper way of doing this would be for platforms such as TikTok and Youtube to create a new feature where people can assign others/friends as moderators of their account's content suggestion feed. Your friends/moderators would then get the ability to see TikTok/Youtube as if they were you. Based on knowing you and your life goals, your friends would teach your content recommendation algorithm what content not to show and what to show more of.
The platform's content recommendation algorithm monitors what kind of content catches your attention but also what catches everyone else's attention. It groups people by similar interests. If your group likes a video, you will probably like it too - so it shows up on your feed. If you abruptly skip it (or outright block it) the algorithm fine-tunes your preferences with that in mind.
So the idea boils down to letting your friends/trusted parties browse as if they were you, but do it with the intent of making the feed maximally useful. Minimize time wasting, maximize education/inspiration/motivation. For people that are terminally ill, it would make sense to maximize entertainment.
Drastic changes should require the account owner's confirmation before they go into effect. For example, if a friend decides to permanently remove (ban) someone's content from your feed, you would get a confirmation prompt to allow/reject it. You would read the friend's explanation about why they are suggesting to ban a specific channel/account from your feed.
Until such features are officially built into the platforms a workaround is to let friends periodically log into each other's accounts and browse/organize the feeds manually.
Nudge the algorithm towards solutions
Friends know each other's problems. For example, someone might be prone to falling for conspiracy theories. Their feed would be dominated by Alex Jones type of stuff. A friend would nudge such a feed to display more science-based explainers.
Follow other people's feeds
Another feature that is similar in a way could be to let people "follow your feed". They could temporarily choose to browse Tiktok/Youtube as if they were another (specific) person. By doing it they wouldn't affect that person's feed, but they would at least see the world from a different perspective.
Education course for algorithm trainers
People should learn the basics of how things should be done. At the very least they should first watch a how-to video that summarizes some useful lessons:
The change to other people's feeds should be gradual. If it's drastic the feed would feel too foreign to enjoy.
Don't make the feed about what you like. Instead, identify what your friend likes. Then emphasize the good stuff, and nudge away from the bad stuff.
What else should people learn before attempting to modify someone's content recommendation feed?
I was also thinking about a web browser addon where the account owner can let his friend interact with Youtube/Tiktok as a pass-through via the owner's own web browser. That would make it impossible for the platform to know that the friend is controlling the browser. That way the platform cannot prevent friends from helping each other out