Modern Vespa

hello all
I bought a vespa pk50xl from 1991 with a new cilinder 50cc, new exhaust sito plus and new dell Orto carburator 16/15. the guy who bought all this could not get it to run properly so I got it for €450. the problem is that the vespa starts really hard, idle is not smooth and does not rev up properly. with choke it idles good and revs also better but it is still not rideable. What I have already done: in the carb was a 65 main jet with seems a bit big for standard cilinder so I lowered it to 53 but still same issues. I have also changed the 42 idle jet that was in to a 38 but also same problems, I replaced spark plug and I checked inlet manifold, it didn't had the vilt ring in it but this is normal I think because the dellorto 16/15 has an o ring in it. when I checked this I put some grease on the o ring and tightened the carb pretty hard to the inlet and it seemed like the idle without choke was a little bit better but im not sure. does anybody know any other solutions? I put a video of me revving the bike up without choke
https://youtube.com/shorts/XSA_XA2GQSk?si=m6a1bIMrZwuOyxhD

Have you checked the plug? Is it coming out wet, black and sooty?

Yes so then I changed main jet from 65 to 53

I'm not sure but worth to try new/another CDI.
Are you sure that choke plunger is works as it should?

I suspect it has to do with the rotary valve since the problems are: cold start very difficult, when engine is warm starts easy, it takes a long time before it revs up when I accelerate, with choke this is a little better, idles not nicely, with choke it does idle, when taking off the air filter I noticed that it was a little wet from gasoline. could these symptoms be linked to a worn rotary valve. The reason i also don't think it is false air anymore is because the moped never revs high by itself. Now i saw on the internet an intake kit from polini with a membrane. this could be an easy way to solve my problem but it is quite expensive. that's why i ask here first if this could be my problem and if so if this kit would be a good solution. thanks in advance!