Since upgrading from 5.16.4 to 5.17.x, suspend is broken for some users. This is still being investigated. Not everybody can reproduce this, getting a useful trace of this bug is appreciated.
See pma#1478 for details.
UPDATE: the kernel has been downgraded to 5.16.4 for now. Using
apk upgrade -a
should get you the downgrade once the binary package has been built.