You may be seeing this a lot for the next couple days so I apologize for the repetition. As @Gargron said, if you want your friends to try Mastodon you should direct them to https://joinmastodon.org rather than one of the big instances directly. It will potentially help spread out the load of all the new users as well as provide some on boarding to help people find awesome services like #QOTO!
@b6hydra could be, I haven't used it myself. I just saw a blog post recently that the algorithm had been tweaked to give priority to smaller instances, so I inferred there was some process deciding what to recommend. But maybe it's just sort order within the categories?
blog.joinmastodon.org/2022/04/official-apps-now-available-for-ios-and-android#onboarding
@khird Yeah could be, I don't keep track of how they're sorted of course. The algorithm they mention in the post is used for the official Mastodon app. I guess it makes sense they would do that to help new users, but I agree with you that a personal recommendation is much better than the results of an algorithm.