The thing is we do not actually know the upper limit of HP spellcasting, the only glimpse we got was the Dumbledore Voldemort fight in the ministry which was quite impressive with tons of
-counterspells/dispells
-some water imprisonment thingy,
-instant creation of multiple constructs or maybe even creation of beings?
-short range teleportation?

In a straight up fight I think d&d wizards could very well lose especially if we consider action economy.

However due to the d&d wizards ability to not ever let it come to a straight fight this does not really matter ^^