can you see openHAB bridge in home app? if not, then the issue is with multicast DNS (mDNS). it can be an issue with docker or with the router in your network
if you can see openhab bridge in home app, but cannot connect/pair, then the issue is with the port 9124. it must be accessible from outside of raspi.
one more thing to check quickly. the IP address configured in the homekit settings. it looks different to raspi ip address visible to outside.
could you try to set the same Ip address in homekit settings? potentially, you would need to switch to host mode again.