I started using a hand held/thumb release with a hook that goes on the string. These types as opposed to caliper types that rotate 360 degrees are stationary and when you draw back to your anchor the string loop is twisted. Is this good?

Just be careful that your loop is not too short. It can cause torque. Sometimes, we think that short D loops are required but they can cause issues.

I wouldn't worry about the 1/4 twist you put in the D-Loop with a handheld release.

As mentioned above if your loop is exceptionally short (i.e. with the arrow nocked you have a hard time getting your release to clip on) the benefits in your accuracy will far outweigh the small amount to torque placed on the string.

Take a look at the guys who shoot serious target archery. All run D-Loops and nearly 100% use a handheld release that puts the same 1/4 twist in the string.