I’m using a free app called SMS block[0] for a number of years. Other than a weird app icon (has a strange logo that has the word TAXI on it with a cross mark for some odd reason), it seems to run local and does the job simply and effectively. Wonder if I need to worry about it leaking any data? I guess it’s easy to switch to Bouncer

[0] https://apps.apple.com/de/app/sms-spam-block/id1283355601?l=...