I have gone through the same process with mixed results.
The initial coating was a clear concrete sealer on a power float smooth floor followed by three coats of grey "Heavy Duty Garage Paint" made by Leyland paints from Screwfix. Unfortunately, after 6 months the paint lifted under the tyres of parked cars and would chip very easily if a tool was dropped. Unable to face emptying the garage, and stripping off the paint I opted for a combination of cheap carpet mats under the tyres of the parked cars which stopped the rubber compounds leaking into the paint and 3 heavy duty polyvinyl floor protectors. The "mats" are made by G Floor in the US and available from Costco in the UK; they are 7.5' x 17.5' and cost £180 each delivered. See link
https://www.costco.co.uk/Tyres-Automoti ... r/p/112281https://www.garageflooringllc.com/blt-garage-floor-mat/They are petrol and solvent resistant, wipe clean and are tough enough for trolly jacks and car lifts.
See below for combination of the three, paint, carpet tiles and floor protectors (ignore the automotive clutter)