I would get a new device personally. I highly recommend the Note 10 Plus over the Note 9. You can find them at pretty good prices used. It's not super old, will still be getting updates for awhile, has faster charging, more RAM, more internal storage, larger screen, wide angle camera, and you can pretty much do all things on the N10+ than you can do with the Note 9, that is, with the exception of the headphone jack and iris scanner and I'm sure a few others. Best device I have ever used honestly.
I used to miss the headphone jack, but it comes with the USB C headphones. So no big deal there. And when listening to music in the car, I use a USC type C to 3.5 MM aux cable. Problem solved.
I got mine Factory Unlocked and Certified, Pre-owned from Samsung for a little bit under 700.