I'm a veteran of a long, multi-year running battle with the two sump pumps in our basement. I can't offer any help because I'm not sure what a tethered float switch is and even more disheartening, in my experience, when you get that problem fixed another one will likely crop up within a few months :)

Maybe try something like this...
https://www.plumbingsupply.com/sumpwatcher.html

"If" I get a chance today, I'll call my pump supplier and see what they would suggest. Also what's on the sump walls to cause the float switch to stick?

I'm confused. If its tethered it goes in a prescribed arch. No? Why would the plumbing company install it where the arch intersects with the wall? Ifso it doesn't sound like they know how to install sump pumps. I had an untethered float and it would get caught on the wall so I solved the problem by tying the hose to the top of the submerged pump such that it couldn't reach the wall. I also have a backup pump that runs off my water line (pressure driven) so if my main pump doesn't work or electricity goes out I am covered. It's float goes up and down on a slide so it cannot get caught on stuff or interfere with other pumpl

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They constantly try to escape from the darkness outside and within
Dreaming of systems so perfect that no one will need to be good T.S. Eliot

Get a vertical float switch. You can google them as needed. Basically they move inside a vertical cylinder, or on a vertical rod.

Try a Little Giant next time. Most of their pumps have an internal pressure switch that cannot be interfered with. Awesome pumps.

The one I had, the cord to the float passed through a clamp. I loosened the clamp and adjusted the position of the cord so that the float didn't touch the sump wall and still had enough slack to be able to rotate enough in both directions to activate and deactivate the switch inside.

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Brian

Gonna buy a fast car, put on my lead boots, take a long, long drive
I may end up spending all my money, but I'll still be alive

This is what I would recommend. I had the exact same problem and fixed it this way. Annoying as hell to go down to the basement and have a couple inches of water. At least it is clean water and not sewage (at least in my case).

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I'm beginning to think that we are much more fucked than I thought.

Thanks a lot guys :)