Please don’t take this the wrong way, but you’re way overthinking this. The procedure for getting an accurate reading of oil level is to check it hot. Not when the coolant is hot, but when the oil is hot. Come home from your ride, turn off the engine and check it immediately. Pull the dipstick out, wipe it, screw it all the way back in, pull it out and check. There’s no splash. If you delay, oil will gravity drain from the tank back into the sump over time. You can get a 3 inch rise on the dipstick between cold and hot.
When oil level is proper, it doesn’t even show on the dipstick when cold. Checking it cold is bad information and shouldn’t be done.
The vast majority of oil level issues on the 998 is just improper technique checking and adding oil. And besides, your riding style and habits would preclude gas accumulating in the oil, anyway. The high oil temperature will evaporate off any accumulation of gasoline.
So, check it and adjust the level correctly. Only when hot. Then follow the trend in oil level. Personally, I think you’re fine. Yes, go forward with that crankcase breather mod. Helps with other issues.