Even good tennis players have awful strokes. Novak Djokovic became one of the all-time greats with an awful overhead smash.
Everything about Daniil Medvedev is ugly, yet he was able to win a grand slam. Elena Dementieva reached world number three with a pretty amateur serve.
Here is a list of the most awful strokes in tennis.
Sara Errani (and the grunts)
Elena Dementieva (deserves to be in the Hall of Fame for her serve)
Sofia Kenin (no-look toss)
Matteo Berrettini (not ugly, but very weak)