Lichess is way more underrated than it seems. I get that Chess.com is huge, but Lichess has some advantages that are totally worth considering - it's completely free with no hidden paywalls, the interface is clean even on a bad connection, and there aren't those annoying ads that distract you.
The community there is pretty active, with tournaments running all the time (from blitz to classical) and you can access engine analysis, openings, endgames - all for free. If you want something more casual and without paying anything extra, it's hard not to recommend. Now, if you're the type who wants a lot of premium educational content or prefers the biggest user base even if you have to pay, then Chess.com makes more sense.
My advice: download both, play on each one for a week and see which one you adapt to better. The choice really depends a lot on whether you get bothered by paywalls, by the interface, and where you find more people at your level to play against.