It's been my experience that rental vehicles are a crapshoot....
Sometimes, if the rental company maintained them like they are supposed to, then they're a great way to save some serious cash & still get a fairly new vehicle....as was the case years ago, when I bought an '09 Impala in 2011 that only had 38K on it was immaculate inside & out. The dealer had all the service records, as well as a clean carfax report....AND it was about $4k cheaper than any comparable "certified pre-owned" Impala that I had already test driven at other places, and over $7k less than a brand new 011... and guess what:
It is still running just fine today, with 250K+ miles & no major issues
However, that was then & this is now. I seriously doubt the rental companies devote the same amount of $$ & labor to maintain their fleets, given the way things are now with minimal staffing and low-quality, near-zero knowledge employees that have no place working around, selling or renting cars...
So they ONLY way I would even be tempted to buy a rental resell car now would be:
A) The price is considerably less than other similar vehicles of the same model, year & mileage
B) The deal included a 5-7 day tryout period, so you could get it checked over by your trusted/qualified mechanic, but return it & cancel the entire deal with a full refund if you don't like what you find with NO penalties or lock-in to buy another vehicle from the same seller (ie..no refunds/only exhange).
C) The seller offers
at least a 5yr/60K warranty at a reasonable cost that covers all major systems, with a zero or low deductible
If these 3 conditions are not at least within consideration from the seller, then you might as well go to a stealership & buy a CPO.
Good luck & please post back on what you end up doing !