New to lexus and new to me is350

Remote start worked at non-Lexus dealer, get home and key fob won’t remote start the car after I logged into the app.

is the app required for remote start? I thought the key fob was enough.

The three (3) year trial that started on Date of First Use (check the CarFax for this) is apparently expired but
the regular key fobs should remote start with a simple button press cadence. With the doors and hood closed,
no check engine light or low fuel light having been on and the second key fob not inside the car...

Press the fob Lock button three (3) times quickly - press / release / press / release / press and Hold.
Hold and wait until you see the various marker lights flashing on their own. Car will start. Will run for
up to 10 minutes or you open a door or trunk/hatch. Can be restarted twice for up to 20 minutes total.

did used-car dealer give you 1 or 2 keyfob?
If there's 2nd keyfob, did you try unlock/lock your door with both keyfobs?

If there's only 1 keyfob, did the red light on the upper right of the fob turn on when you press 'lock' or 'unlock'?
If not, it's time to replace battery in keyfob.

usually used-car dealers swap out the new battery & replace with dead/old battery to scalp another $2-8 off you.
this is the reason why I dun buy anything pre-owned.

In Asia, South/Central America, Middle East, African continent, Eastern Europe & Russia, they even swapped out all OEM parts in your engine, transmission, wheels, tires, lighting, dashboard for fakes.

And I believe this practice has reached our shores in North America, even among private sellers.
You see same authentic pre-owned vintage Patek, Rolex & AP watches with fake parts sold by long time 2nd hand grey dealers in all watch forums with NYC shops since 1990s.
So I bet the same thing for all car makes

2 fobs, both batteries have been replaced and red lights are presant. Clicked 3x and held on the 3rd up to 10 seconds in some tests.

I thought you didn’t need to subscribe to the Lexus app for remote start via the key fob.

Also, the windows won’t roll down when holding unlock.

you do have to enroll in the Lexus App unfortunately.

The remote window roll down and related key blade in the driver's door window roll up functions
are defaulted off when new and can be enabled by the Lexus mechanics using the Tech Tool computer.
Would have been free at either of the 5K or 10K complimentary service visits but would likely be done
for a fee after that. If you are a regular and/or multiple Lexus owner that patronizes the shop they might
perform this service for free. There is a civilian app by Carista that can do it, I've not used it but thought
I read that it is geared toward non-Lexus shops because it also has a subscription to use.

Signed up for the app, remote start works now….bunch of BS