It's probably a no brainer but the 2017 is black on black with luscious "leather" seats so logic is at risk of being ignored. Please help. In one corner is: 2017 Toyota prime Premium, with 66k mi. @ $14,500 The other option is: 2021 Toyota prius prime LE, with 112k mi. @ $15,500 Both with 2 owners, reasonably maintained and price a bit negotiable. My 2008 is fast approaching 200k and the original traction battery is showing aging symptoms. It is however top of the line so I've been spoiled with real leather seats, JBL 12/18/whatever speakers, multi keyless, etc.
The 2017 is known to have exhaust gas heat exchanger issues and black cars in SoCal tends to get really hot. You'll need to ceramic tint the glass to cut down the heat. The 2021 can do Android communication; while the 2017 may be Apple only if they can communicate at all. Somewhere in there they became Apple aware. Both are still under the Ca. 10 year 150K mile EV power train warranty. Hope this helps....
if you're sitting in those luscious leather seats on the side of the road because the head gasket blew, at least you'll be comfortable