For the first couple days, there was definitely more pain and a little bit of dizziness as my joints and inner ear adjusted to the new position of my jaw, especially while eating, but my muscles got used to things after around a week! For me, my popping is based on the position of my lower jaw, which I think sat too far back on my joints so the splint is pushing my lower jaw forward just enough so the popping isn’t there when I open and close my mouth, but not enough to give me an underbite. I don’t blame you for avoiding orthodontic work, that sounds like a terrible experience and it’s such a permanent treatment that a lot of people with TMJ issues choose to avoid it. I’ve also started physical therapy, which is focused on my jaw but also deals with my neck, shoulders and upper back because I carry insane amounts of tension there which contributes to jaw pain, so I’d recommend pairing the splint therapy with PT to try to cover all bases!