I’ve got 3 holsters. My favorite is Kydex IWB CYA. It’s safe, and I like the single clip because it’s very easy to take on and off. It’s not the most comfortable, BUt it’s affordable and easy to use. Not sure if it qualifies as “deep concealment”.
I have an alien gear 4.0 IWB. This might work for deep concealment because you have a lot of freedom in adjusting. I did not like this holster the day it was delivered, but after I started using it I really liked it. It’s pretty affordable. It was hard to move some of the parts at first but it wears with time. It appears bulky, but it really conceals well. I seriously pondered returning it the first day I got it, BUT I really like it now.
I like comforttac belly band. They make one for deep concealment. I use mine when I wear sweats of gym shorts. It works really well. My only concern is drawing the gun also requires releasing a button. It is not impractically slow IMO, but Kydex is definitely faster. However, it allows me to carry during times where I wouldn’t.