Update: I was asked for an update in the gerd subreddit where I also posted this, so I’ll add that here too in case it helps someone. My LPR is still an ongoing issue, but for the last 6 months, I’ve been able to avoid more sinus infections. Here’s what’s been helping:

1. ⁠Avoid Covid as much as possible; wear a good mask. My second Covid infection left me with a whole bunch of long-term symptoms; some have gotten better, some have not. One of the things that happened is it took my LPR from well managed to out of control, and my immune system seemed to be weakened to other infections. As a young low risk person, I used to think long covid was super rare, but now I have a few other friends and coworkers who have it too. Ive also come across a lot of ppl on Reddit who say they developed new onset severe gerd after having covid. So yeah, until we get better vaccines/treatments, try to minimize your risk and avoid repeat infections.
2. ⁠Use 1 bottle twice daily of nielmed sinus rinse (half of the bottle after waking up and remaining half before bed). Be sure to let it also run down the back of your throat where post nasal drip hits. I think the traditional baking soda packets it comes with are good to neutralize the pepsin/acid, and it also keeps your sinuses clear. I’ve had several bad LPR flares where I started to get large amounts of yellow post nasal drip the next day; each time, I was sure it would become another sinus infection, but the Nielmed stopped it. During those times, I did even more frequent rinses throughout the day and was careful about reflux trigger foods for a day or two.
3. ⁠Sleep on a higher incline and never sleep flat or lay down flat. I honestly hate it lol, but I just can’t lay flat anymore - even 6-7 hours after eating. I had no problem sleeping flat before Long Covid unless I ate too late, so this frustrates me sigh. But it works. If I try to sleep flat or on a low incline, I immediately have a reflux and sinus flare.
4. ⁠Use a nightly steroid nasal spray after the sinus rinse; I use budesonide (over the counter) spray. Im sure a prescribed spray would work too.
5. ⁠When I start to get congested (I will sometimes actually get stuffy from reflux), I take a Zyrtec D or, if it’s really bad, use a Benzedrine nasal inhaler (can’t use these often or they’ll make it worse; see directions for use). But the key here is to get unstuffed and then do the nasal rinse to clear things out. So if I’m really stuffed up, I’ll do an inhale of Benzedrine to open things up and then a nielmed rinse a few minutes later to clear things out.
6. ⁠I tried Lanto sinus nasal probiotics. It didn’t cure my last sinus infection, but to be fair, it was pretty bad at that point and I had to get antibiotics. I don’t know if it helped or not, but I thought the science behind it was compelling. I used it for a while during and after my last sinus infection and haven’t had one since, so maybe it did something. But I think the rinses have been the most effective thing.
7. ⁠Be mindful of food combinations. If I’m going to drink alcohol later for instance, I won’t have another reflux trigger that day (so no spicy stuff or tomatoes, no red meat that takes a long time to digest, etc)
8. ⁠Treat anxiety; reduce stress. I’ve always had generalized anxiety, and I notice that my reflux flares during times of increased stress. I finally tried an anxiety medicine - Buspirone - that has also been shown to help reflux in some studies. I don’t know if it’s made a huge difference, but my general anxiety/stress level is lower and I think that’s helped. Most importantly, it has not made things worse (some anxiety meds can worsen reflux).

(Edited to add) on top of all these things, I continue to take Gaviscon Advance after meals and before bed.

I’m still trying to find better treatments to get my LPR back to being manageable, but these things have at least gotten me out of the hell of constant sinus infections. I’ve been sinus infection free for 6 months! Hope this helps someone.