You would first need an actual working RISC-V silicon that it would be worth porting to. Not the essentially demo chips with poor performance that are around now.

RISV-V is a lot of talk and hype but the actual silicon that you could buy and implement into a product is hard to come by. With the exception of a few small microcontroller efforts (GigaDevice, Sipeed).

Android still works on x86-64; indeed there are quite a few actively maintained x86-64 Android ports that are used, both on bare metal PCs and virtualized, for various purposes.

The problem is that there are no x86 SoCs that are sufficiently power efficient to be battery-life competitive with ARM SoCs in phones.

MIPS support was removed from the Android NDK, though older versions of the NDK stand a good chance of working, still. So app developers with components needing the NDK support have a bit of work to remain compatible.

It might pretty much work today, perhaps with a few config file changes.