Going on sort of a tangent, but since it was mentioned: I hate variable refresh rate.
I suppose my eyes are just sensitive to changes in rendering speed, because I tried it and I couldn't stand the variable ghosting. For me it's worse than screen tearing, which for me is perfectly resolved with vertical syncing or just capping the frame rate to something less than my monitor's refresh rate.
You could probably fix it by capping your game's framerate to whatever it can maintain consistently within your monitor's VRR window. This would give you a smooth consistent experience, without screen tearing or vsync-induced lag. Since it's not working in a fixed refresh rate container, you can do more unconventional numbers too. I like to run a lot of games at 90 FPS.
First off, I almost never get screen tearing. The only times I get screen tearing is if a program renders faster than my monitor can refresh, and my monitor (a Dell S2522HG) refreshes at 240Hz; screen tearing simply isn't happening. As for input lag, if there is any it's insignificant enough that I don't care.
Second of all, my problem is with the the way variable refresh rate works and not with anything on the software side or the monitor itself. Variable refresh rate is exactly what it says on the tin, the refresh rate varies.
My problem is because the refresh rate varies, the difference in refresh rate becomes very distracting. One moment my monitor is at 240Hz, the next at 135Hz, then 170Hz, then 70Hz, then 200Hz, and so on for an exaggerated example. Anything that's moving (eg: my mouse cursor) leaves more ghosts the lower the refresh rate becomes, and vice versa. This is very distracting because it's not consistent.
Imagine you're listening to music, and the pitch goes up and down arbitrarily. You will probably agree that it's distracting, and that's basically what I find variable refresh rate to be. It is distracting to a fault, and I would rather deal with my monitor going at full speed and limiting my software as appropriate to prevent tearing for a consistent experience that isn't distracting.
I have a VRR monitor, but I limit it to 120Hz specifically for that reason. Most of the time it just sits there. The exception is while gaming, where sticking to 120 was never an option; I find the variation less of a bother than the more dramatic shifts down to 60/30 would be without VRR.
My suggested fix should still solve your other problem, which is the wild swings in framerate. Bouncing between 200 is 100 certainly is jarring, and capping your game's framerate to make those swings smaller or nonexistent will fix it.
It can be a bit of a curse. LED headlights and taillights give me headaches. A lot of LED street lighting and business lighting hurts me. Etc.
I used to be basically unable to stand a CRT under ~85hz. :(