Generally with hands as weak as ATo this is going to be a fold. You have enough stronger hands you can 4-bet all in with to ensure your opponent isn't getting the best of you.
That being said, if you have 3-bet stats on them and see they are 3-betting in those positions 15-20% of the time, ATo becomes right on the line but still not that strong. In fact a better hand to 4-bet jam with would be KQs because most of their 3-bet bluffs will be with Ax and so you don't want the ace blocker in your hand.
Now I digress, the easier adjustment to the situation is to tighten up your opening range even more so than you can 4-bet all in a higher % of the time when you open. It may seem kind of crazy but opening 88+, AQ+ will allow you to do this, and if they aren't adjusting their 3-bet ranges you'll be getting the most of them a ton of the time.
You can also consider raising to just 2x or 2.5x since you're playing with shorter stacks and can easily get all in on the river with these open sizes. It will also cost you less when you have to fold to the 3-bet and give you better odds when you want to call it with your suited broadways and good but not great pairs.
Hope that helps, and know that they are risking quite a bit in that spot so it's ok to be folding 67% of the time out of position (and ideally more like 50% of the time in position)
Thanks for your positivity as well, brought a big smile to my face