De,
I'm a little confused by what you are reporting. Maybe it's just my understanding...else it may be your dosing.
First, it makes NO sense that standard Netti pot use, with ONE packet of the salt which comes with it dissolved in ONE potful of water, should cause ANY significant discomfort. The SARS-Cov2 protocol calls for 2x day for 14 days.
The salt is just there to make the solution isotonic with your blood, body fluids, and what your cells usually deal with (if it is not isotonic it could cause pressure across the cell membrane). But what is this about 3-1/2 tsp??? If you are using 1 packet, I would expect that to be more like 1/2 tsp?
When I diluted iodine 10 to 1 (that means 1/10th iodine in 9/10 water, just to be sure you follow), it caused some slight burning sensation/discomfort. So I diluted it to more like 20 to 1 (10%/20=1/2% iodine) and the discomfort/burning stopped. Try that. Or try without the iodine at all.
There really shouldn't be pain. Yes, the first time you do it, it may seem stressful, but after that it shouldn't be a problem.
Also, don't try to hard to "force" anything. If the water doesn't flow through, because your nose is inflamed or there is too much mucus, it doesn't flow through. The point is to rinse, not to do some sort of hydrojetting under pressure.
Put in some solution from the netti pot and then gently BLOW IT OUT (not too hard). A couple times in each nostril, gently, should be enough to dislodge anythng there.
Personally, if I feel my nose is stuffy, I actually put in a little water and then "snort" up gently, to get the solution higher into the sinus. But don't do this if you nose is already uncomfortable.
Another thing to add to the protocol is to gargle a little with the 1% or 1/2% iodine solution, and then spit it out. This gets to any viruses which may be in the back of the throat. There is actually a commercial 1% iodine mouthwash which advises this for sore throats, etc. So you are just making your own.
Anyway, if done properly, with properly isotonic saline (or a little less salt might not hurt) this shouldn't be something you can't do safely and easily 2x or more a day...even 365 days a year!
Maybe Drop the iodine for now, only use ONE packet with one pot of water, would be my first suggestion, and see if that feels better?
Also, on ivermectin, I would say that if you have taken 1/3 tube two days in a row, take a break from it for day three. If you don't have symptoms of Covid, I might suggest you don't need any more that week. The 1/3 tube was my rough guess of what would be safe and yet would be large enough to hit the virus hard (presuming it had already started multiplying). The second day of 1/3 of the tube should bring your circulating blood level high enough that you likely don't need more for some days. (If you had active symptoms I might continue, but for prophilaxis 2/3 of a tube should be enough.
Oh, you remembered to take the ivermectin on top of a little food with some oil in it, right? I would say at least one egg or something. That food with oil increases uptake into the bloodstream. Without food, ivermectin will mostly just go through your bowels quickly. Without food is for worms. With food is for blood uptake.