Taping can help, I’ve found with maternity belts it takes practice to get them in the right place. My first one it took me almost a month of frustration before I figured it out. This time I had to get a new one since my old one is missing, it took me 3 tries to get it right. It sits front super low over my pubic bone because that’s where my belly ends, then back I need against my lower back so it usually sits across my hips on the sides. Then I use the extra straps to adjust for a snug but not remotely tight fit.

What about trying that athletic tape? I can’t remember the name.