Taking some local examples, look at Cam Calhoun (went from Utah to Alabama) and Tausili Akana (went from Texas to BYU)

Both those guys hit the portal and were reevaluated by 247 for a transfer rating. Calhoun got a 90, Akana got an 85.

Calhoun was rated a 90 as a prospect, dropped to an 89 after limited time at Michigan as a freshman and then back up to a 90 after a very good RS Freshman season at Utah.

Akana was a 96 as a HS prospect (though even then reviews noted his weight was unverified and "Position projection will be dependent on verified weight and growth potential"), didn't put weight on or play for two years at Texas and dropped to an 85.

But whether or not you agree with those (and 247 is definitely handing out lower transfer ratings this year than they have in the past, previous years' ratings were VERY inflated imo and they seem to have overcorrected this year)...the important thing is that those ratings were assigned well prior to the player committing anywhere.

Cam Calhoun was rated a 90 before he signed with Bama. And if he'd signed with BYU he'd still have been a 90. T. Akana was an 85 BEFORE he signed with BYU and would have been that same rating whether he ended up at BYU, Utah, Washington, or Ole Miss

That's not conference bias as much as we want to call it out as such