I don't have a ton of faith in tplink to continue to support omada over the long term. They've also been somewhat slow to fix security problems in the past. For the same price as the omada ap you can get unifi u6 lites.
You can still run your own controller and i can vouch thaf a couple of them can cover an entire moderately sized house. I run 2 at home with pfsense on an ewaste tier dell optiplex and have for years without trouble.
I've never messed with opnsense but I assume it works just as well.
Also what type of connection are you getting from your ISP? If its a fiber connection you may be able to buy an SFP network card and replace the modem altogether.