This still sneaks in pieces of rpm into distros where rpm is not needed so better would be to retool dnf to not demand rpm support in libsolv and break the dependency chain. Opkg is usually sought for small systems and last thing we want is unneeded dependencies
I would rather use the OE configuration powers as such but I am not opposed to such a solution
You can always set these things (rpm disabling in libsolv, blacklisting libdnf/dnf) in your distro configuration, but I would like less complexity and special-casing in poky, not more, for the pieces that I maintain at least.
Alex