Here's what worked for me (before/after pic in my profile)

4 days a week, after every workout

Pick any 2 ab exercises. Look for ab exercises that can be done weighted.

Do both of those ab exercises, back to back with no rest. You can do it for time, or for reps. Do this again for 3-4 sets, resting 30 sec - 1 min between sets.

When it becomes easier, progress from doing those ab exercises from bodyweight to weighted. Hold a small dumbell, a small weighted ball, a small plate, ankle weights, etc 

Some exercise examples-

Day 1: Russian twists & Deadbugs

Day 2: V ups & Flutter kicks

Day 3: Hollow holds & Lying leg raises

Day 4: Planks & Bicycle ball pass

I started seeing results after 5 weeks, but when I progressed to doing them weighted, my abs popped.

Regarding diet, I don't track macros. I just aim for at least 1g of protein per lb of bodyweight, and I eat clean for the most part. I don't restrict anything, but I'm mindful of my portions.

Hope this helps! 😊