I'm not sure Tyler was radicalized while at college, especially since he didn't stay long enough. If you look at the mom's old Facebook photos, Tyler was wearing masks and doing covid protocols during his senior year, and possibly junior year as well. If he was like a lot of covid year students, he was very likely getting school at home and also stayed home a lot due to businesses being closed down during covid. That is likely where he encountered discord troons and other radicalizing content. If he did get radicalized at University despite not being there long, I believe it's because he already had the foundation laid from covid.
I'm also wondering if the reason he couldn't tough it out at University despite appearing very smart is due to spending so much time at home and online before getting sent off.