The best I’ve seen is have additional contributors (often who just like the project but aren’t coders themselves) who run interference for the dev team. They can triage feature requests, filter out the spam and repeat issues, etc.
Also, and this can be the hard part, is sometimes you have to have someone who (even politely!) can be a bit of a dick when necessary. People scan be quite entitled and want to boss everyone around and tell them the project is run wrong - if you don’t actively run at least some of them off the devs will curl up and disappear.
Also having a defined procedure for “hiatus” helps quite a bit - make it easy for a dev to say “I’m off” and it can be indeterminate - this allows them to easily come back later. Encourage devs to use it liberally.
Also, and this can be the hard part, is sometimes you have to have someone who (even politely!) can be a bit of a dick when necessary. People scan be quite entitled and want to boss everyone around and tell them the project is run wrong - if you don’t actively run at least some of them off the devs will curl up and disappear.
Also having a defined procedure for “hiatus” helps quite a bit - make it easy for a dev to say “I’m off” and it can be indeterminate - this allows them to easily come back later. Encourage devs to use it liberally.