@chessknt is spot on with the assessment of what allergy looks like
Feel free to DM me and I'd be happy to talk in more detail. Training burnout is real and that is likely what you're feeling. My day to day practice is great. There really isn't any need to prechart or anything like that. I get it and I did it initially (out of habit and neuroticism, mostly). Once you're in practice and get the hang of it, you don't really need to pre chart. You're not getting many complex, multidisciplinary care referrals. You're mostly getting straight forward patients and probably not even getting records sent for most of them anyway. Call is a joke, pretty much none of us do hospital consults. I guess if you're in a small practice, you might be fielding patient calls after clinic more often. If you're in a bigger group and especially if there are midlevels, your call burden will be minimal, very minimal. The inbox of an allergist is probably better than most outpatient fields. We don't order a ton of imaging or labs compared to other fields. Hours are normal and controllable. Most work 4-5 days. The earning potential is good. Your anesthesia buddies will make more initially but your earning potential is probably higher than you think. You're also have good potential to have plenty of autonomy as an A/I doc. Still plenty of solo practitioners and privately owned groups.
I think anesthesia is an appealing field but I can't imagine how you could ever consider giving up a career as a subspecialist with a great lifestyle and solid earning potential to go back to training. The thought of it makes me think you are just burned out and engaging in some kind of escapism or grass is greener syndrome. On a practical level, it's pretty crazy. You just spent 5 post grad years training and you would attempt to spend another 4 or so training to change fields this late in the game? I wouldn't consider it a negative to not have to deal with complex PID, HAE, or that type of stuff on a day to day basis -- I love dealing with bread and butter AR, asthma, rashes, food allergy, etc. The patients almost all get better, they are grateful, the reimbursement is good, and you mostly have positive pt encounters all day. Those complex things aren't always as fulfilling. PID can be interesting but you're correct that you pretty much have to be at a large pediatric hospital to see the rare stuff. HAE is meh -- the pts can be difficult to deal with (for whatever reason), the meds are expensive and require paperwork, the actual management is pretty straight forward (controller + abortive, options often dictated by insurance coverage rather than personal choice). Drug allergy is either pretty straight forward or you're dealing with some multidrug intolerance BS.
If you were a med student deciding between A/I and anesthesia, this would be a different conversation. I actually think anesthesia seems like a great field and I wouldn't try to talk anyone out of it. In fact, if I was back in med school knowing what I know now, anesthesia is probably a top 5 field in my opinion. I don't really have anything negative to say about anesthesia. But you're at the finish line of 5 years of post grad training in a desirable field...I don't see any reason to give that up. I get it. I've looked at the grass on the other side and thought it was greener. I have friends in great fields like derm, ENT, ortho, and I've thought "man, should I have done that..." but I have never thought about going back into training. I don't know if I have another second of training left in me. The whole system of training is so toxic and burdensome. Getting out of that bubble and going into private practice was such a breath of fresh air. Don't get me wrong, there's BS to deal with...but I think this is true of any field and I think we have it pretty good.