When another app did this (horrible unity ads which also blasted audio in what was otherwise a silent app) I developed a reflex of closing and reopening it. Eventually they went away, so I expect that was most people's response.
Considering I can't even look at Instagram without a login, which I don't have... nothing of value was lost.
Instead of the Instagram app, use the mobile web version in Brave Browser or Firefox with the ublock origin extension installed (which, the the way, can be installed on the mobile version). Perhaps keep the app for notification purposes only if you find them useful.
I understand the requirement for "free" sites to make money, but this is going too far.
This really makes me feel old. I just don’t see the utility in any Meta product at all. And this kind of thing makes me realise that point even more. The #enshitification continues.