4 Years and no karma… Help

I’m a long time lurker I mainly use reddit read or learn more about certain communities, im not a consistent reddit user so I’m kinda still a noob so i don’t really get what’s important but recently I’ve been using reddit more and I keep running into the same issue with my posts been taken down instantly because I lack Karma i think, My account is 4 years old so I woulda thought that account age would be more relevant I don’t get why karma is so important to be able to post in certain communities. Is it my karma why my posts get deleted instantly and if so what’s the best way about fixing that?
Thank you.