I believe my husband bought it from wayfair but I found the same one on amazon
It comes with a big enclosed cat bed area but this guy rather hammock so we don’t get much use out of that
https://www.amazon.ca/Pet-Products-49923-Wall-Mounted-Lounging/dp/B01IK50RLI
You might consider getting something like this air filter: Amazon link
And there are foods you can feed the cats to reduce the stuff you are allergic to.
Maybe those in combination with allergy treatments will make it possible for you. :)
Edit: eventually, not immediately. I know allergy shots take time. And if you do adopt, consider taking them to a groomer that can bathe them or at least thoroughly wipe them down to remove the dried saliva from their fur to reduce the “load” they bring into your home.