Stops at Delta for sure, you could argue he stops before her but I'll just go with Delta

Boro is pretty much confirmed to be more powerful than Delta so why is Delta at 4? Anyway, I would say Boro but it will be a long fight due to the regenerative powers of both 🕷

Wait where does it state Boro's stronger than Delta?

I think Code says it after she gets one tapped by Naruto.

This?

If so then it could just refer to Boro having better abilities or hax that are more suited to use against Naruto.

This is further supported by this statement:

Yeah it's those two.