I found that prop 121 time alone was not enough, except for SWA. I observed after the brasilia retired at SKW, within one year former bro CAs were leaving in droves once they got a jet type and a few hundred hours to go with their years of prop experience.
There is more training risk for prop drivers going to an advanced jet. Although the Q is a lot more sophisticated than a bro.
Prop time is not wasted, all or almost all of the people in my legacy class had both prop and jet time. But I would have a plan to get jet time in your hip pocket if you're in a hurry.
If you're not in a hurry, they should be hiring everybody in five years.