Here’s an interesting thing to try.
You will need a length of stretchy rubber tubing. You can get it from Amazon and other places. It’s not expensive. The trick is to get the biggest thickness you can manage, and that may need some experimentation. We find that a diameter of 4mm or 5mm works for us. Actually, we find thicker tube easier to use, but maybe that’s us.
You need a good length of it, 1m or longer perhaps. It needs to be thoroughly cleaned.
You need to feed one end down a nostril and out of your mouth. Gagging is the issue, but you get used to it. Then feed the other end down the other nostril and out of your mouth.
This has a technical term. It’s sutra neti.
There are loads of examples of it on YouTube and elsewhere.