An endorsement is useless without any time FLYING IT!
A turbine is not like a piston twin, i.e a couple of laps around a circuit with a touch of airwork and a couple of hour chat prior. Most are up to two weeks of intensive ground school study, rigid examinations and long periods with a checkie until you are signed off to fly the line.
Companies that I have flown with will spend 50-100 hours with you before you do fly the line so a 'bare' endorsement is not going to save them much money unless they require a skipper with time on type. Even if you are a skipper with lots of command on type, you will still go a refresher ground school and 50 hours line flying with another checkie before you are signed off!
The only endorsement that may help you is a C208 and even then most companies worth their salt will upgrade and train you to fly it.
I suggest if you want to fly a Turbine start looking into companies that fly in areas that are not popular that have them. Mount Isa is a good example!
If you wait until March next year and get as much multi command as you can I will bet that you will get a FO gig somewhere as there will be a trickle of movement again provided the GFC does not go into the W shaped recovery or there is another scare!!!