I used to have trouble opening jars.

I went looking for one of those "jar openers" and someone in the Amazon reviews suggested a strap wrench. They were right. They are much better. Maybe a bit overkill for jar-opening, but better to be overkill than not enough.

These gizmos are for putting a lot of torque on something large and round, like pipes. Hardware stores have 'em. There are several types: some have a metal strap, others a nylon strap, and others a rubber strap. For jars, you want a rubber strap.

You can even get two, use one on the lid and the other on the jar.

One random example (not the one I have):

https://www.amazon.com/ACOSEA-Wrench-Diameter-Adjustable-Plumbing/dp/B0C9YF82ZL

Note that (since this is a $1 discussion) these things are more than $1.