Modern Vespa

Hi Guys,
I'm trying to help a friend out.
He has a 2023 50 cc Vespa that won't stay running. Sometimes it starts hard other times it won't start at all.
If it does start it won't take any throttle and dies. Unfortunately he doesn't have a shed or garage so it sits outside (it has rained a lot recently).
It has less than 100 miles on it and "did" run fine up until a few weeks ago. It sounds like it is starving for fuel but when I check the fuel pressure the gauge reads 36 PSI, which I think is in spec.
Things we've tried: new spark plug, drained fuel tank, put new fuel in it, new injector, I had a spare injector for one of my bikes (also a 2023 50 cc) so we swapped it, removed/cleaned air filter, removed the exhaust to see if it had a blockage -- no difference. Battery is at 12.8 volts and on a maintainer. We checked the valve lash, intakes are at .010 and exhaust is at .015.
I feel bad because he bought this bike because my wife and I have so much fun on ours. He's actually ridden my wifes a few times and loved it, hence why he bought this one. He bought it used, it ran fine last year and all the way up to a few weeks ago.

Any ideas?
Thanks in advance.

would check the compression.

That is it.
Only 60 PSI while cranking with throttle open, only 30 with throttle shut.

Thanks for the recommendation.