How to get better with OTB chess?

You can use my own free and open source software in the link https://github.com/karayaman/Play-online-chess-with-real-chess-board to recreate the OTB experience while playing online. You can download latest release from the link https://github.com/karayaman/Play-online-chess-with-real-chess-board/releases

Yes, there is a gap between online chess and OTB chess. The viewing is different, the conesthesis is different (your fingers feel different things). You see your opponent in front of you. It is in fact different. So maybe it helps also if you play some games (i.e. old, important games) with a real chess board at home. Or you set some chess problems on such a real board and try to figure out what to do.

Just practise tactics with a physical board. That may help.

I learnt to play chess without computers, and I like to calculate on a physical board. For me is easier. I reproduce games from books also with the board.