Cherry picking.
Vederian Lowe had 13 penalties. Cam Robinson had 13 penalties.
Lowe allowed 5 sacks in 502 pass block snaps. Robinson allowed 7 in 632.
Lowe allowed 5 hits, Robinson 7.
Total pressures allowed: Lowe 33, Robinson 52.
That is not a clear upgrade.
PFF grades, taken with a grain of salt, Robinson grades out slightly better pass/run, 70.4/59.9 for Robinson, 66.9/45.8 for Lowe. That could be viewed as a minor upgrade if you like/care for PFFs grading.
Robinson is likely a slight upgrade over Lowe for a substantial investment in capital, which you so desperately want them to part with. He's not worth the money, especially when you take into consideration his Trent Brown-like proclivities.
Joe Noteboom is probably a slight upgrade in the run game, but not great in the passing game, while likely costing a fraction of the money.