I would bet dollars to donuts, that Rhule watched game films, and saw where, in his offense, or in his OL philosophy, he would have done things differently. Or in conversations, Raiola shared what he was told to do with the OL blocking scheme as compared to what Raiola wanted to do.
I also don't believe that Rhule kept Raiola for the simple goal of getting his nephew. If your OL is going to suck, then you aren't getting the QB regardless if the OL coach is his uncle.
As was stated earlier, QB Raiola was still committed to Ohio St when OL coach Raiola was hired. Frost with Raiola couldn't land the QB, so that methodology already failed.
It will be interesting to watch what QBs for 2024 are offered in the next few weeks now that the 2023 class is almost complete.