My 2019 RX 350 is probably my least favorite and it certainly has had the greatest number of issues of any vehicle I've ever owned. To be fair, nothing huge and it's never left me stranded, but still annoying.
1. The 8-speed is a hot mess. Too quick to upshift and too quick to downshift means it's in a constant gear hunt. When I first bought the vehicle it had a weird delay when hitting the throttle and a subsequent hard clunk as it downshifted. There was a TSB to reprogram the transmission which I had done and it improved it a little but still not great.
2. There is also a very noticeable shake/rumble in the drivetrain when in drive and not moving. When I pull up to a stop light it's significant enough that change rattles in the cupholder. I brought it in for service and was told they all do this and it's normal. Sure enough, they let me drive two test drive cars and they did it. I've had several loaner RX 350s and they all do it too. Weirdly, I've driven two Toyota Highlanders with the same drivetrain and they did not do it?
3. Engine is super smooth, quiet, rev happy but has no torque and no personality. There was stutter in the engine when I first bought it and it had to go back in for a TSB to reprogram the ECU. No issues since the TSB was applied.
4. Needed new brakes at 20K miles. My wife is very easy on her vehicles and does the same thing she's been doing for 8 years and no other vehicle she's driven needed brakes until at least 40k miles.
5. Needed new tires by 25k miles. My wife is very easy on her vehicles and does the same thing she's been doing for 8 years and no other vehicle she's driven needed tires until at least 40k miles.
6. Fit and finish of interior is subpar. I've had the car in twice for front door rattles. They pulled the doors apart and applied a foam kit that mostly took care of the issue. Everything is soft-touch but it feels like cheap soft-touch.
7. Infotainment went out needed replacement. Oh, and it's terrible BTW even when it works. My wife only uses BT streaming and she controls what's playing by her phone because the interface is too much for her to figure out. The little joystick is terrible. I think they changed the screen to touch screen in later year last model vehicles.
8. Rear power tailgate failed and needed replacement.
9. USB ports in the center console needed to be replaced.
As for my personal opinion - it is my least favorite car to drive of all time. It drives like a brick on wheels with heavy understeer - my Tundra handles significantly better. There is still a type of hesitation on acceleration from a stop. Before the TSB it was much worse but when you hit the gas nothing happens for 2 seconds and then it takes off like a bat out of heck. Part of that may admittedly be because as you see the car coming to T-bone you and you're not moving you instinctively hit the gas more - when the engine decides to wakeup it sees heavy throttle and takes off. As I said earlier, the 8-speed constantly hunts gear because it upshifts and downshifts too quickly. Hit the gas just a little and it downshifts immediately. Let off the gas just a hair and it immediately upshifts. Rinse and repeat no fewer than 8 times going up a ½ mile long hill I drive everyday. Get to speed on hill, keep constant throttle, and the engine has too little torque so it downshifts. Start going faster and let off the gas to maintain a constant speed and it upshifts. Bogs for a few seconds and finally realizes it has downshift. If the transmission would just hold the downshift going up hills it would eliminate much of the aggravation. Last, seats are nice but they are not particularly comfy on long drives.
All that said we still own the car and we plan to keep it until it dies because it's mostly paid off and while I hate it, my wife loves it and she wants to keep it. To each their own...lol.