Crazy thought - could you put a sump pump on the outside of the house at a couple corners and achieve the same thing as having it in the house?
Like our basement is a walkout and the one corner is the problem corner, so I had the idea to put a sump pit/pump outside at that corner to pump before the water level even gets to the point where it would leak in.
I did text one of my plumbing clients to call me tomorrow or monday to discuss.
Seems like it could at least help to pull water out of the low point. Drain the downspout into it as well.
Only downside vs a regular sump seems like it would have the potential to freeze and more potential for debris to get in there.