I'm pretty sure that you can use both. RAs even have bits to indicate if one is supposed to autoconfigure, [0] hit up a DHCPv6 server for some or all configuration, [1] or both. radvd refers to them as AdvAutonomous and AdvOtherConfigFlag/AdvManagedFlag, respectively.
[0] <https://datatracker.ietf.org/doc/html/rfc4861#section-4.6.2>
[1] <https://datatracker.ietf.org/doc/html/rfc4861#section-4.2>