You guys that work out what fo you do for the belly region? I work out about 5 days a week but I sure as heck don’t do any core stuff. I just focus on arms, chest and shoulders. Need to at least try to get some core and mid work in. It just doesn’t excite me.

The best thing for the midsection is continued cardio and a good eating plan. Building muscle under a layer of fat won’t look any better. Body weight exercises like pushups and pull-ups are good for the core

Abs are made and kept in the kitchen between caloric deficient and light cardio. As far as Core-engage it in all major lifts will work it enough but for additional work I will add a finisher of crunches, hanging leg raises, or decline leg raises 2 times a week and will alternate with calves as a finisher on opposite days.
Like Biscuit mentioned-you can build them as much as you can but will not show if body fat% is not low enough.
Mine are the last to show in a cut and the first to go in a bulk-but everyone is different

The visibility of abs and a flat stomach is 99% diet and body fat related

You need to check and see if you have an abdominal wall separation (diastasis recti) https://www.doctorshealthpress.com/general-health-articles/diastasis-recti-in-men/ There are specific exercises if that's the reason for you bulging stomach.

Honestly if you are working out 5 days a week your core is probably getting plenty of activation from the other exercises.

I rarely, rarely train my core. I maintain strictly thru diet and exercise of major muscle groups.

I stopped working out in a gym and only do HIT work outs with sandbags and kettle bells.

I switch it up. Conventional exercises that you know like sit ups, bicycle kicks, Roman chair and planks. Lots of planks for me. This along with a full body work out and hitting the keto diet hard core once or twice a year for for a month or so.

It sounds like you are asking how to build your core, and not how to get ripped abs. Abs and core are not the same. Once you understand this, you can begin to target your actual core. It is possible to have a 6-pack but a weak core. Your core consist of many (about 20) different muscle groups., including lower back, stomach, hips. Your abs are part of this group. Many body builder type folks can have bulging abs, but if you give them true core exercises, they will shake like crazy. I know this from experience. If you are shooting for overall health and strength, do lots of core work. Look up exercises like the "dead bug", planks, hollow rocks. If you are shooting for killer abs, concentrate on diet and ab work. But 90% diet.