There is no way to answer this question without more information.

What types of games do you like? Do you care about glitches or not? Do you like long runs or short runs?

And although you’ve made it clear that you don’t want to see “a game you like”, that is still the best advice. We could sit here and recommend games for weeks, but if you don’t like the games we recommend, it won’t be fun for you to run them and you’ll get burnt out quick.

"inb4 a game you like: no" Why not? That's really the best way to get into speedrunning IMO.

Anyway, since you've taken that off the table, your other best option is to check out the Streams page and check out some runs, and see if anything looks interesting to you.

Start at the earliest platform with graphics you can stomach, and select only games that don't currently have any runs on this site. Instant WRs will boost your confidence.

Megaman battle network chip challenge I got the wr in 3 weeks and the game does 90 percent of the work