Sounds like it wouldn't hurt to get the tires road force balanced. When you said your mechanic put in new suspension, does that mean shocks? Or is new suspension springs, shocks, and all rubber parts? There are almost countless causes for death wobble. The condition of all rubber puts in the front suspension should be inspected and replaced if needed. The track bar bolt on the front axle side is also prone to getting worn out to be an oval shape, causing death wobble. You should also get it aligned if it hasn't been aligned in a long time. Not having enough caster can cause issues too.
@boxyjeep is somewhere in Cali, so he might have some shop recommendations. I would encourage you to learn how to do a lot of this stuff on your own. These are fairly simple rigs. Obviously there are some things that you can't do, like the tire balance and alignment, but working on other suspension stuff can be done fairly easily.