I've owned 5 prior rental cars and drove them well past 100k without any mechanical issues that could be attributed to abuse or being rented. In fact my dad bought a 2003 suburban from enterprise and has more than 300k on it now.
for 14 years I drove 1-2 rental cars per week in locations all over the US (47 states). While I’ve been in some that were very nice, I’ve been in others that were total crap. Rented from Hertz, Avis, and Enterprise. The last few years before I retired in 2018 the quality of Hertz units really dropped, started seeing cars with 55k + miles, trashed interiors, etc. it seems they were keeping units in the fleet a lot longer than in past years (previously were always <30 k miles. I switched to Enterprise as my prime and found much nicer, lower mileage cars. I’d be VERY careful with any former rental. There ARE some that are great, but there are also some bowsers out there..
I'm in a loaner-rental now. It's a 2020 Grand Cherokee. I noticed the oil change is about 2K miles over due from what the oil change reminder sticker noted. I toggled to the oil life reminder and it was at 0%. I wonder how long it has been at 0%? 1-2 overdue oil changed probably won't hurt a engine but it is something to consider when buying a rental or loaner. Any used car for that matter.
I have to say back in the 90s I got a rental Wrangler Cozumel. They took out the front driveshafts to discourage people from 4 wheeling in them. They told me that and I thought "OK. Challenge accepted". Enough speed (and Mexican beer) and the momentum will get you through just about anything.
Back then the southern tip of the island was destroyed hurricane wasteland. The current park with the lighthouse was an abandoned ruin. I looked like the guys on the show Rat Patrol except I was jumping dunes in the Caribbean and not the Sahara. That was the most I had ever abused a vehicle. It was fun. I chose a different jeep when I turned that one in.