Advice on code throwing original HV battery in low-ish mileage 2008

I’m the 2nd owner of this relatively low mileage (120-140k? Ish) 2008 Prius that hasn’t given me any problems but for my 12v battery abuse, and taking a beating from a couple natural disasters (‘totaled’ 2ce so far, but mechanically & structurally sound, just not pretty).
Well, coming home from a 40min drive, I was dazzled by a light show of the triangle of death & probably others, but that one was enough to make me pull over on the country highway. But, this was the one time I didn’t have my phone, so I started it back up to get to somewhere I could get help. And, that’s where it truly gave up the ghost; electrical turns on, but no motor, inoperable.
My mechanic said it had HV battery codes alight, but dopey me, I didn’t ask which. So, I’m at a crossroads:
- order by mail a refurbished battery for $1k and just DIY replacement w/o ever diagnosing the battery (core return postage paid)
- same joint in FL, $2k for new
- fork over the $ and have the nearest tech drive the 2.5hrs (at least $200 to show up), then worst case scenario, if still need a refurbished battery, they’ll charge $1400 plus the service call.
I did toy w/ the idea of getting an economy scanner compatible w/ iPhone & android , as we have 2 gen2s and a gen3. But, I don’t expect I have either tools or know how to do much w/ the info, besides perhaps, drive the battery the 2.5h for repair, if it’s more likely to be in better shape after repair vs reconditioned. ???

My battery hasn’t been garaged in brutal hot humid summers & freezing winters & car has often only been used a few times a week for a few miles/trip (fill up tank once a month, or 2 months? if not busy).

Ideas? Advice? Comments? Questions?

[My other dream plan is to also buy a low mileage 1 owner all maintenance records PiP that’s been in comfortable weather its whole life, as well. Then use one for business. Would be nice to have a backup vehicle & nice to have more justification for solar panels. PiP would essentially be electric almost all of the time, unless going out of town (rare). I figure stock isn’t going to get any better than now w/ the sun downing of the fed clean car credit. Only sticky bit is I’ve only bought cars from private sellers before, in person - only 2ce. And if buying a car from a distance, finding a good hybrid mechanic to do a thorough pre-purchase inspection, so I don’t have the willies about buying sight unseen. Oh, and dealing w/ dealers & dealers’ pricing, the horror, eep!!!]

Complex enough for 1 thread?