FIDE

if I have 2000 in rapid (10+ 0) how much will it be FIDE. about . who will say something?

I say "search the forums"

1650. If you expect more you have to prove it.

mathtuition88.com/2017/10/26/lichess-to-fide-elo-rating-conversion/

It is quite dated, considering that the lichess rating system is not very stable and expiriences a lot of inflation and deflation over time. Overall i would subtract 200 points to get a rough estimate. and the conversion between categories is bad as well, so yes take evey thing with 2 grains of salt. Lichess rating was the most inflated arround 2016-2017 when I had just "peaked" over 2200, now 2100 is tough for me. Anyway to get a FIDE rating you have to play FIDE tourneys anything else is just speculation.

Using Rapid and Classical rating, I don't think it is a good comparison because very few people play Rapid and Classical in lichess. If you want to have a rough estimation -

Estimated Fide Rating = Stable Blitz Rating (Min 100 games) - 100

If you see many IMs in 2400 rating it is because often they berserk and don't play seriously.

dunno about inflation and deflation. But one thing that may have changed a bit dividing the old Classic into rapid and classic. But anyways any estimate from one pool to another carries accuracy of max +-200 pts. So here we agree: You realy wanna know go and play

OTB tournament chess is rather different from playing online chess. I suggest you to find a local chess club and play (long time control) OTB games first. Get high FIDE rating on tournaments can be very difficult if you has no stamina to sit and concentrate for long-long hours. Playing rapid/classical online games will never substitute playing real OTB games!

@Sarg0n, haha, I’ve about 2000 in rapid and about 1900 classical but only 1400 FIDE classical, so... :)

2000 rapid on lichess could be anything between 1300 to 1900 fide.
Different rating pools, not comparable.

Are there many time controls in OTB tournaments? Like for blitz for example, are there as many as in lichess? If not I do not see how to compare unless we play online with the same they use in OTB.

I find this thread not very motivating to move to OTB as even some good players here might end up with bad ratings while they felt here they knew chess quite well. Are there any games or sports more competitive than chess to reach top level?

I feel the level is already high here. Some masters sometimes play 1400 rated people and although they win, they do not always break their defense so easily if the 1400 rated player does not blunder in the opening.