Opinion= I spend $1k on a paint job, $3k on new battery =I can go another 10 years with a decent Prius
If you prefer that over a new one, sure. $4,000 is a lot less than $24,000 (or whatever the starting price is of a Two). Pocket that $20,000 and invest it so that you'll have a hefty down payment later.
It is highly optimistic to think you can drive the Prius 10 more years without other issues happening: transaxle, inverter, AC compressor, engine, suspension, etc.
I say go for it. You have nothing to lose. You now have zero depreciation in your TCO calculation. You can spend two thousand dollars per year on repairs and still be ahead. If you can, find someone to replace your battery modules with a 2k1Toaster kit.