personally, i would put a fresh plug in (i've been advised to run an iridium plug in my 280) , put fresh fuel in and give it go. i think the recommended mix ratio is way too rich, i was getting loads of oily goop out of the exhaust and difficult starting on the recommended ratio.
with 100:1 ( 50ml per 5L ) mine starts fairly easy and runs good.
they say there is a knack to the gas gas stating, personally i just ease the kick start over until its engaged at the top of the stroke, then give it a solid quick full stomp .
just did a 6 hr long lap trial on the weekend , and it started first kick most of the time. my only issue is trying to get used to the sharp power delivery in the slop we ride here in Wales.
good luck, i hear the '23 models are lovely to ride.