You need more than 45.5% equity here because there are three players left to act behind you.

It’s also worth noting that whether villain is shoving GTO or not is irrelevant if we’re trying to play unexploitably. We just need to decide whether we are trying to do that or not. In this case, since we think we can make a reasonable read on what we think villain’s range is and what the players behind are overcalling, we can probably make an exploitative adaptation. However, we shouldn’t stray too far from Nash ranges, because we do have limited info on this player beyond population reads (can’t tell what the buyin is from your post).

My guess is that A8s is going to be right on the border of that range, but I’m not sure. With tight players behind us I might go with this, but if they’re going to be calling somewhat correctly behind then I might ditch it.

If we have a read on our opponent that we can exploit (population/player pool reads do count here) then we should try to exploit it, but if we’re readless we should be at least attempting to use Nash ranges in these push/fold spots, and play as unexploitably as possible in other spots.

If villain is shoving Nash here, then we call Nash, very simple. That’s the most profitable decision, there’s nothing we can do to increase our profit beyond that point without a read. If we only have a read on the players left to act behind, that could lead us to call very marginally wider, but that would mean we would no longer be calling at Nash, and the villain who already shoved may then be exploiting us.

Honestly, the best way to answer these questions is just to get a calculator like HoldemResources Calculator or ICMIZER and run the calculations yourself. That will teach you more than posting a push/fold hand on the forums ever could.

Also, I apologise for phrasing my first sentence poorly in my first reply. I meant to say that the reason why you need more than 45.5% is because you have three players left to act, and not necessarily because you actually need to have a 2.5% cushion in order to be better than break even on calling the shove in a vacuum. A lot of people fold away far too many edges in these spots, so waiting for a 2.5% cushion every time is going to cost you a lot. It just so happens that in this particular spot with players behind, having a cushion is desirable.