Is it possible to upload a pgn-file that includes many games, and not only one? So I could browse th

Up to 20 it says. but that was five years ago. "In a study, you can now import a PGN with several games inside (up to 20), and it will create one chapter per game. Enjoy!" https://lichess.org/forum/lichess-feedback/new-feature-study-multiple-pgn-games-import