Looks like a massive crop to me.
It could be nothing is wrong and OP just isn't used to grain. Having said that, a 5x7 enlargement from a relatively normally exposed and developed 35mm TMax 100 negative should be extremely fine grained. Developed in Ilfosol 3, the negative would be grainier than if it were done in XTOL or D-76, but it should still be very fine grained.
Neopan 400 is not exactly a fine grained film so the prints would be very obviously grainier than prints from TMax 100, but still pretty fine grained at this enlargement size.
High contrast printing will also emphasize the grain in the negative.