I searched for many people with the same strength, but they are all gone!

Search for anyone better than you lol

I don't really co-op that much, but here are a few ideas:

1. Try to find someone that has roughly the same time as you (maybe a 10-second difference at best) and make sure they're active

2. if you haven't, you should join the community discord; there's a channel in there that could help you look for suitable companions

most people don't look at speedrun.com messages. active people at your level include @LionCoder10, @tadgoodatgaming, and @Mo88