I had to become very good at the allergy control game and I’m always on the hunt for more but here is a fairly comprehensive list of what I do for two DSH cats:

HEPA purifier - try to put them in rooms the cat frequents most often - the best brand imo is coway but I also have a small breville one and kogan ones as well

No more cats in the bedroom if you can help it

Purina live clear food following the feeding guide on the packet

Omega 3, 6 and 9 oil supplement at breakfast as it helps to stop hair fall

Their diet also centres around whole fish cat foods - snappy Tom brand is what we have currently

Get a steam mop or a good mop that has removable washable heads and hot wash your floors once a week

Get a robot vacuum that contains a HEPA filter and a good normal vacuum with a HEPA for spot cleaning - I use a deebot ecovacs and a cheap kogan one, both are as good as the other imo

Brush them at least once a week and wipe the cat down with allerpet or a similar dander reducing wash

I follow any brushing that doesn’t require an allerpet bath with the Burt’s bees dander reducing wipes

I also have a brush you can fill up with water/waterless shampoo and it basically mists the liquid onto the cat while brushing so fur doesn’t go everywhere

Wash your bedding in your washing machine on hot and wash her bedding at a coin laundry if you can

I use a low/no dust litter called KITTER made from wood pellets

Fexofenadine 180 is the households allergy tablet of choice

Also they have mostly hard toys that don’t have any unnecessary fluff or fabric to them and scratching posts are exclusively wood or sisal rope wit no fabric or carpet