Literally ask them if they find the reports useful. Say that if they don’t, then you’d rather spend that time trying to grow their business. Let them choose how they use your time.
Additionally, get familiar with Google Data Studio. All reports are completely automated. I haven’t manually put together a report for a client in well over a year. There are templates out there you can use, and you can edit those to fit the needs of a specific client. Set it up once, and you’re done.