Manual? I don`t see a manual for a 2020. I would get a 10tooth and a 48. You might get to know Stu at Jackscycles.com or try the trials store.
https://www.trialstoreusa.com/front-sprocket-gasgas-vertigo/
The KTM dealer will not be much help.
Go to your Gas Gas dealer and get 1 tooth smaller on your counter shaft sprocket. The gas gas always had too tall of first gear for tight sections.
PS who is your dealer. You should have a 46 to 48 pilot jet.
Best way is to take it completely off the bike. People are just too lazy to do it right. You can hang it by the caliper and use a phillips to pump the m/c. This works the easiest because the trapped air can go straight up. Otherwise the air stays trapped at the banjo bolt. You can also take a 3 foot clear hose up and over the rear fender. You will still have to crack the bolt at the m/c.
Our 2018 RR has done 22 events in the master class and the Ute Cup in 2018 which is a 80 mile event of mostly single track. Most of the plastic looks new. Have only replaced the water pump seal once.
I would buy a left handed drill bit set. While drilling you might get lucky and the bolt just come right out. Throw away the torque wrench. The only place on a motorcycle to use one are the cylinder head bolts.
If it really is a short finger issue, as it happens. The only way to get the lever closer is to grind a little off the push pin. That is the little part the lever pushes on. Just take a little off at a time till you get it right.