family sharing

It's not so much an issue about devices but of members. Up to 6 total IDs can be part of Family Sharing. However, View and remove your devices that are associated with Apple ID purchases - Apple Support

says, "You can have ten devices (no more than five computers) associated with your Apple ID for purchases at one time." So I guess that would be 60?

Max. of 6 Apple IDs. Each Apple ID can have up to 5 computers and a mix of up to 10 computers and iOS devices. Apple TVs & HomePods don't count towards those limits. Potentially 60 devices. See Authorization vs. association - Apple Community.

tt2

I don't think there's a limit on devices, but there might be a limit on how many family members (SIX).