They still allow you to do monthly installments using Apple Card without actually contacting the carrier (I checked by trying to order a 14 pro *after* that change was made. You just have to “choose” a carrier and may be required to activate with that carrier first. They should also be unlocked, so this shouldn’t change much for you in terms of ordering phones this year for your and your wife. Us too are on a t-mobile business plan, but if you choose Apple Card monthly installments, select “activate with any carrier” then choose T-mobile (in my case as an example), it shouldn’t actually reach out to T-Mobile prior to you checking out in my experience.