I have a similar issue. I have a IPv4 client which establishes a wireguard connection on his own to a remote server.Whenever I reboot Opnsense the wireguard connection is stale forever. With 22.7 I mitigated this by enabling 'Dynamic state reset' which has been removed in 23.1. I now have to manually reset the state table to ensure after a reboot that everything works.
Couldn't this option be enabled for specific IPs only? like on ip change flush states of a specific client/IPthank you