Everything except LM is a title you have to apply for via fide, uscf etc.
LM= Lichess master a title bestowed by an admin who think a player deserves for for excellence in chess at
lichess.orgThey are usually players who are good community members and have high strength in chess spanning across many variants the site has to offer.
FM= fide master usually ~2300
CM= Candidate master usually ~2200
IM= International master usually ~2400 with norms against grandmasters
GM = Grandmaster usually at least 2500+ reserved for players who reach the highest standard of performance in chess.
There are other titles as well.
The only advice I can offer for getting above 2000 is to study chess and practice every day. Do problems, read a good chess book even get lessons. But you can always teach yourself, just that a good teacher will be better able to pinpoint the areas you are having trouble with and remedy them.
I think your goal should be to improve, not just focus about titles. Some people are naturals at chess and start out at a high rating. Some are mediocre and stay that way forever. Some are bad and stay bad. Some are okay but get better with tons of study and practice. Remember that your online rating is a reflection of how you compare to other lichess players, not EVERY and ALL chess players. The focus is chess obviously so naturally people with some experience with chess will gravitate towards here.
You will have to work hard to improve your chess game but it will be worth it. This game is rich with history and value. Chess reflects your personality, it is a deep tool of insight.