Agree completely. While both texts do largely focus on people of Jewish origins, there is not a lot of actual overlap on content. Some of the NT books are seen as prophetical, so that lines up to some degree - but even those read very different.

It's not just content that differs either - the literary style of the NT also deviates greatly, since it borrows much more from hellenized culture than the OT. Especially the synoptic gospels. For example, John, was composed using a layered "onion" type narrative structure which was popular in other greek texts.

They're even so different, that one form of heresy that was more common back in the day (Gnosticism), would sometimes claim that the OT deity was a false-god (the demiurge), because how else do you explain such a personality change?