They’re both too weak to be worth paying money for.
Get a HEPA air filter (filters out bacteria, fungal spores, and viruses) with a UV lamp (probably doesn’t make much difference, but doesn’t significantly increase the cost). I have this one and like it a lot:
https://smile.amazon.com/Germ-Guardian-Purifier-Allergies-GermGuardian/dp/B00OLBR084/
Edit: if you want to kill germs on surfaces, use bleach or any cleaning spray that says it kills germs. UV not required.
That's a rough battle to be having. Went through a similar situation in a condo we were renting. I sealed off all openings from below (plumbing, electrical, etc), and we got a couple of these air purifiers, and that seemed to help combat most of it.
Another thing would be to add a weather strip to the bottom of your door, or put a towel across it to block any air coming in fro the hallway.
They don’t have to be big! I have the below HEPA air filter and its footprint is around 4” by 4” (10cm by 10cm): https://www.amazon.com/Germ-Guardian-Purifier-Allergies-GermGuardian/dp/B00OLBR084
I’d put the HEPA in the bedroom, and the dehumidifier in the bathroom.
HEPA air filters are free standing.
Germ Guardian True HEPA Filter Air Purifier with UV Light Sanitizer, Eliminates Germs, Filters Allergies, Pollen, Smoke, Dust, Pet Dander, Mold, Odors, Quiet 28in 4-in-1 Air Purifier for Home AC5350B https://www.amazon.com/dp/B00OLBR084/ref=cm_sw_r_cp_api_glt_fabc_N8G0RJKJZFY6FTEZAEWE?_encoding=UTF8&psc=1
A nice air purifier like germ guardian will do wonders. You can use beeswax candles or melts but only unscented. I personally use the wax melts cause they’re weaker and no wick burning seems a bit safer to me. Here’s a link to the air purifier i use
Germ Guardian True HEPA Filter Air Purifier with UV Light Sanitizer, Eliminates Germs, Filters Allergies, Pollen, Smoke, Dust, Pet Dander, Mold, Odors, Quiet 28in 4-in-1 Air Purifier for Home AC5350B https://www.amazon.com/dp/B00OLBR084/ref=cm_sw_r_cp_api_glt_i_EKR2NPZSF25S5Y4E2EHP
If you want to purchase a different one make sure you find one that will not produce ozone which is super harmful to ferrets and humans
Fun fact. Living with a cat can help build up resistance to THAT SPECIFIC cat's allergens. When I hang out with a cat from outside of our home, I have a more pronounced reaction.
Good luck and don't give up on the kitty. You saved it and it will love you forever for it (just don't let the food bowl get empty!)
HEPA air filters will get the smoke out. I have this one:
https://smile.amazon.com/Germ-Guardian-Purifier-Allergies-GermGuardian/dp/B00OLBR084/
It’s reasonably priced for a HEPA air filter, and it’s got a very small footprint.
I got my mother this one:
https://smile.amazon.com/gp/product/B01728NLRG/
It costs a bit more and has a bigger footprint, but it’s much shorter so could be put on a shelf with a bit extra clearance, or under a desk.
HEPA air purifier. Either one for each room, or put it in the bedroom when sleeping and if needed move it when you’re in other rooms.
I have this one and love the small footprint of it: https://smile.amazon.com/dp/B00OLBR084/
My mom has this one and I love the power of it: https://smile.amazon.com/gp/product/B01728NLRG/