if you feel like the coach's training isn't working, is rash, or is causing your injuries, such that you need to transfer, why would you believe if you give it more years you get any meets or times out of those future years, either? won't you have the same problem next year to get there? that needs to go into the calculus.
re worrying your future, you should have every bit of your 4 years of eligibility left as either a medical hardship or normal redshirt. that should help your case if you do have good HS times and a decent current school, as you would be almost like a freshman for their purposes. ideally you would have good grades this year too. worst case you apply to some teams where TFRRS tells you that you should make the team, and contact them about joining. if nothing else a school where your history suggests you would make an impact should be eager for your walk on. to me as long as you can explain what happened and that you are healed, you're better situated than if you ran lousy times hurt and you look like an illusion. try selling that instead.
if you want to move you need to do the portal because if you don't you risk NCAA saying you have to take a year off in residence at school 2. the portal is an exception to the year off rule -- it gets you your free transfer without the cooling off period. last thing you want is a medical year off followed by a transfer rest.