After I got my J-pouch my daughter convinced me that we should study Japanese Ju-Jitsu together, and to my surprise we worked hard enough and spent long enough at it that we both became instructors. My pouch was the reason I *could* do that, rather than a reason I couldn’t. But Japanese Ju-Jitsu mainly trains cooperatively rather than competitively, and I only took a small number of direct strikes, so my experience was different from what you are planning. The pouch is really (mostly) in the pelvis rather than the abdomen, so I’d guess that other organs (e.g. your brain) and your knees are at greater risk than your pouch.
FWIW when I’ve worked with MMA-trained folks they seem compelled to take the fight to the ground. This is a fine strategy for a cage match, but a terrible self-defense strategy, since you can rarely be certain about whether there’s a second attacker.