Is there a manual fast, wide and cheap APSC prime lens for the RF mount?

[crish580]

I have a canon m50. I use samyang 12mm f2 for milky way and a sigma 150-600C for birding.

I'm planning to switch to R7 or R10 with the RF100-400 lens for birding. So is there a lens equivalent to samyang 12mm f2 for the RF mount?

[Waddizzle]

I have not researched it.  Is your Samyang 12mm EF-M or EF/EF-S mount?

Why don’t you just use the Canon EF-RF mount adapter?  You’re going need one for the Sigma 150-600mm, anyway.