What is wrong with BananaPi? My understanding is it used for the basis for the OpenWRT community flagship router.

I wouldn’t be surprised if it performs adequately in this context —- isn’t the manufacturer a VOIP device maker?

The reality is that they spam the market with a large number of products with little consistency, poor (if labyrinthine) documentation, random google drive links for firmware etc., and there are the same issues with hardware support.

I dunno, maybe the situation there is better than it was. But the broad picture is the same: better hardware but you are basically on your own.