i even purchased two $150 air purifiers and gave him a third to be placed throughout the home to help with air quality.

Get a high quality air purifier/scrubber, seal up(caulk) any cracks or gaps that could be allowing air flow between the units. 

Or do you have an air purifier/filtration system built in, sometimes that runs on a timer to filter it.

When people go over that amount, charges are for additional oversight, chemicals, purifiers, etc., for additional water.They more likely will agree to a payment plan, not a "settlement."

You are breathing some in now unless you are in some kind of hermetically sealed air purified chamber. 2.

Two dogs over 60 lbs, and it's just when you walk in at the end of the day and there's been no air moving around when you get that"musty" odor and there isn't a specific location it's coming from.We vacuum regularly, cleaned the carpets recently, bought a $350 air purifier, mop/dust, etc - it's still there.  

Old (like original) Playstation, tower air purifier, board games, and anything in the kitchen is fair game from silverware to crab pots.

There are various types of odor eliminators available in the market, such as sprays, powders, and air purifiers, which could help neutralize the smell.Replace Damaged Items: If any carpets, rugs, or furniture have been damaged beyond repair due to the dog urine, you may need to consider replacing them.

I'm considering getting an air purifier or ozone generator that can quickly clean the air, especially w/Covid and cleanliness concerns.

I have only used it in one home so far that was a 1200 sq ft home.Enerzen Ozone Generator 11,000mg Industrial O3 Air Purifier Deodorizer (11,000mg - Black) https://a.co/d/eBSL5dV