Being confident is one thing, but being completely arrogant is something entirely different without the tools to back it up.
If he had his pop's athleticism then he would've been picked already.
As a quarterback, how you conduct yourself is extremely important as you're the defacto head of the team. Throwing teammates under the bus and bombing interviews isn't ideal.
At this point, teams are looking for backups and Shedeur with Deion looming isn't worth the headache to most teams. He needs to actually be his own man now as he attempts a professional career.