Try a totally unscented/no additive litter in a new litterbox that has no odors. If you take kitty with you when you shop you can see if any of the boxes seem acceptable (don't repel kitty). Their sense of smell as a lot more sensitive than ours.
The plastics/recycled plastics in some litter boxes are problems. The chemicals added to litter can be a problem. Adding cat urine to either/both of these sources of chemicals/odors can cause chemicals/odors to be released.
I use Special Kitty... plain, unscented clay...
Try cleaning the floor and any washables with a baking soda and water solution. Do not use vinegar.
Try putting a freezer/refrigerator box of baking soda near the litter box.
If kitty persists, try mixing some baking soda into/onto the litter.
Did you change any cleaning/laundry products before this behavior started? Air fresheners, candles, etc.? Hand soaps/moisturizers? Hair products? Car products? Did the manufacturers change any formulas (they all seem to think we all want that nasty Axe/Gain fragrance in everything). I get sick from it and presume it's bad for my dog and cat, too. There have been some FDA-mandated changes in products recently, too. Anyone new in/visiting the house? Any changes in anything they use? Any routine changes? What about pesticides/weed killers/mosquito repellents? New furniture, carpet, etc.?
Maybe put an appliance tray (used for washers, hot water heaters, etc.; get at Lowes or Home Depot) under the litter box. They are are sweep or wipe clean (dry or wet) and will protect your floor near the litter box from accidents/on-purposes. I use Clorox Clean-up to sanitize. Afterwards, after drying, you could use a baking soda/water rinse if you want to clean off any bleach residue.