I've had no issues with my acrylic hard tubes, not sure where you're seeing failures due to pressure.
I make sure my cuts are straight, usually sand it down with sandpaper on a flat surface, then chamfer (hope that's the term) the inside/outside edges with one of these:
https://www.dazmode.com/shop/waterc...-internal-and-external-reamer-deburring-tool/. If you're bending the tubes, make sure you aren't over heating or over working them. And make sure it's not too long either where you're putting unnecessary strain on the tube once its in the fittings.
If you're really concerned, I think something like this:
https://www.dazmode.com/shop/waterc...-fittings/air-exhaust-fitting-silver-shining/ would help relieve any pressure in the loop too if you left it open, though at the same time that means letting air in all the time too I would think.
The only time I had an issue with pressure build up in my loop was when I was feeding water into my reservoir with a pump without having any opening/drain. I don't even recall closing the drain port. That blew out the oring on my GPU block and leaked everywhere, but my hard tubes and fittings were fine. Really stupid mistake on my part