[Bosco]

I read the Didache here (all versions), and from the context it's not singling out a "priest" to perform the baptism. The audience appears to be Christians in general.

Only reference to priests is in chapter 13, and the subject is prophets being treated as "high-priests".

I think you're assuming that it is addressed to priests but the content and context doesn't support that assumption.

So, it's an instruction as to how to baptize but it's not specifically directed to priests.

Looks like a difference to me. Then: any Christian could baptize. Now: Roman Catholic priest baptizes.