How do you maintain friends

Heyyy I lack quite a bit of social skills and since a young age I have had trouble maintaining friendships. I think a little bit different then the average person because of reasons just like my family. I never knew how to maintain friendships so I started acting different to keep the friendships going. The way I started behaving tho was basically acting really retarded. People laugh constantly at my dumb behaviour but it keeps the friendship ongoing for a while, because they like my company just in a way that messes with my self esteem. I always wanted to make people laugh and enjoy my company but I'm not good at making jokes I suck. I also don't really share the same humour with people so this was the only way to keep people near me. Also I don't really share the same interests with a lot of people and find it difficult to talk about subjects that we can talk about that keeps a friendship going.

The problem is tho that people underestimate me a lot. They think that I'm easy to use because of how retarded I act. After a while they don't really see me anymore as a person you should respect and start using me and such then it just develops into a very toxic friendship.
I'm constantly the laughing stock and the things they think of (my) behaviour keeps floating in my head. When I walk over the street I get sooo self conscious. I constantly think everyone must think I am so stupid. I litteraly can not even talk to people I might be able to become friends with because of age and such, because I think they don't want to talk to me cause they think I'm dumb or cringey etc.

Most of the toxic friendships I'm no longer in, but I have some newer friends and I really don't want to mess it up this time. Every time we are in a discord voice call as a group. They only laugh about my stupid behaviour it makes me so insecure after the calls. It really is messing bad with my mental well being right now since of the lockdowns and all it got so much worse. I quit studying because I was so scared of being judged so basically social contact. I am even to self conscious to go to the supermarket I can't go alone. I know that I should just stop acting so retarded but since I have been doing this basically my whole life I do it unconsciously. Every time when I feel like I'm not pleasing someone enough with making their time enjoyable with me. I start acting like that. I know I might need help from a professional but I'm not financially capable to do so and my health insurance doesn't cover it. So basically my questions do you have any tips for me to help get a healthier base for a friendship?