More info please.
How much is your plan if it was just you? Are you getting a set reimbursement for having a mobile phone, regardless of the actual cost? Or are they looking at the bill and paying 100% of what is yours (so if a single line costs $80/mo vs the $60/mo it does now...would they pay the full $80?)?
If that's the case, then there's really no reason for your wife to stay on your account. I mean, if you were choosing between paying $80/mo for just her on her own AT&T account, vs combining the two and saving both you(r employer) and your wife nearly $25/mo each, that's a no-brainer. But if that's not the case, then you have options.
I'd look into Cricket. They're known for having some good phone deals, especially with the iPhone. They tend to be locked to Cricket, but can be unlocked (for free) after six months of service, so set the calendar to alert you just after six months has passed (you don't want to cancel in a year to jump ship to a better provider, just to find out your phone's locked to the prior provider; at best it's a hassle, at worst you have to start the waiting period again). Anyway, Cricket has a $40/mo plan that comes with 10GB of high-speed data (you're not cut off after 10GB, you're just severely throttled...so no more Netflix on the go, but you can still use Google Maps to get to where you're going). Bonus, Cricket is owned by AT&T and uses the same towers, so she probably won't notice a difference in service quality (I say probably because you just never know for sure). You could even look into switching both services over, they have some decent family plans. The Cricket More plan is $90/mo for two lines ($90 total, not per line), comes with unlimited (and definitely throttled) 5G data and 15GB of hotspot data. You can get cheaper plans if you don't need unlimited super-fast data, or are ok with data caps, or....
Now, if you must stay with the current setup, just keep an eye out for iPhone deals through AT&T. Walmart had a decent deal where it was $5/mo for 30 months to get a new iPhone SE, but you could pay it off early (it didn't actually extend your contract by 30 months or anything like that). If you can hold off a bit, I can all but guarantee that there will be some awesome deals for older iPhone versions on Black Friday (the iPhone 13 or whatever they call it should be released by then, so everything will move down a spot...iPhone 11 will now be two generations old and will likely have some really good deals).