I’ll probably just install .1 and have a play then reinstall .2 from fresh and transfer my data.

There’s no need for that. X.1 -> X.2 is a minor upgrade, there’s no reason to wipe and reinstall for it.

OPNSense is a great option for turning x86 hardware into a router. That said, I would not recommend combining your router with other functionality. The router should be a dedicated system that only does one thing. Leave your NAS and web services on another machine.