Both those are for line activation, not switching devices. My main line currently is with AT&T small biz and I've moved from Pixel 6 Pro > 7 Pro > 8 Pro by just popping the sim in. No charges. When tmo postpaid was my main provider, same thing, charged once initially and that was it. For tmo prepaid, I currently have family on lines and again nothing beyond the initial sim charge. And as I recall, esim is free (as it should be).

If you don't go to a store for assistance or do something weird (try and move from a phone to a tablet or something; and that limit is only for postpaid lines afaik), there should be no fee. It's only when you involve a staff member do they charge you for assistance. Unless tmo changed the policy for postpaid lines in the last 2y, my experience doesn't match yours o.O