Am I wasting my time.

If you make no effort it will be hard.
check this: www.thechesswebsite.com/queen-vs-rook-endgame/

If you enjoy trying, it's not a waste of time.

I've tried to learn endgame Q against R also - put in some hours - and have resigned. It is very hard.
My rating 1970 rapid.

See if Chapters 18-25 in my study here helps:
Non Pawn Endgames: QKrk: Use the Fork

@ozturkdk , the technique is to sandwich their king with your Queen and King. ( So you should split your King and Queen )

You better use against endgame tablebases ( Stockfish may or may not be able to play 100% perfectly like tablebases and training against imperfect opponent may get false security)

syzygy-tables.info/

I still say "I have made no effort so far" was funnier!

Now stop mocking a non-English player. He used one wrong word that might have a similar translation to Danish. And concluding from his name, he might even be a Turk living in Denmark. So he has done more effort (yes!) in learning languages than most of these mockers who happen to have English as their first language.

Actually GMs fail usually. Kramnik once said he wasn’t sure to succeed.