Chastity and orgasm denial discussion

I’m a 22-year-old guy with an uncut penis. A few months ago, I bought a CB6000 to test it out. I wore it for about two hours. The pressure was incredibly high, pressing my foreskin hard against the urine opening. After those two hours, there wasn’t any pain, but the tip of my penile head was red and puffed up as if I’d been stung by a bee. It took an entire day and some baby rash cream to heal completely. I promised myself I would never attempt chastity again. A month later, I opted for a Bon 4 device instead. The experience was similar; even though the Bon4 felt comfortable, the foreskin pressed firmly against the wall, causing swelling and redness. Still scared off from trying chastity ever since. Having spent $300 on devices so far, I just want to understand why this happens and why it takes a full day for things to settle back down? Has anyone else dealt with this? How can we reduce pressure on the foreskin? (Note: I did try retracting my foreskin, but then the sides turned red and swollen.)