Belly (fat) support for cardio exercise?

I’ve had a NSV (yay!) is that while the scale has gone up a little, my belly has had a loss. The downside is that instead of a solid (fat) belly, I now have a loose, flabby but heavy belly.

It really hurt tonight when exercising and I’m sure that can’t be good (the same sort of pain as exercising without a sports bra).

I’ve looked at support belts, but they all seem to promise to melt fat (haha). That’s not what I want - I want flab support so I can exercise at my fullest. I have had back problems, so want to strengthen my back, and not do anything to weaken it.

Can anyone recommend anything?

Thank you!