Background: 2021 (US) Himalayan, purchased in February 2022. Now has 4600 miles on it. It had significant stalling issues, mostly solved by the booster plug. No other modifications to stock bike.
Problem: Over the past week or more, starting has gotten progressively worse, hot or cold. Wednesday I rode it for about four hours at speeds up to about 63mph, usually about 55 mph, to my Dad's place. The return trip was at a bit more relaxed pace. Thursday morning I took my granddaughter to school (on the bike) in the morning. It was extra fickle about that start, but did get underway. The ~50 mile trip was otherwise normal. Friday evening I decided to ride to a store about 15 miles away. I could not get it to start (cranks but only fires a little, no smell of excessive fuel). Having some time, I disconnected the booster plug and restored the stock configuration. The bike fired up easily and made the trip to the store, though the engine noise was less than what I am accustomed to. It refused to start when I was ready to return home. I pushed it to the gas station across the street to eliminate the possibility that I just was too low on fuel, no joy. Roughly an hour later, it did start, but I couldn't keep it running while putting on my helmet and gloves. It wouldn't fire up again. Today, I retrieved it from the parking lot, visually checked the fuses and fiddled with (removed and reinstalled) the two relays under the seat. The battery was too weak to crank it well, so I put it on charge.
And more: Throughout my ownership, the battery has been unable to crank the engine well starting on the compression stroke. It typically gets past compression in a second or two, then cranks normally. I have no idea if this is something peculiar to my Himalayan or many of them require more to crank than the battery can easily provide. I mention this, since I don't know if the battery voltage is dropping too low during cranking for the ignition and fuel injection to work properly. Curiously, the fuel gauge seemed to be functioning as a voltmeter when I tried starting it with a weak battery, as it read lower with successive attempts.
My apologies for the length of the post, I just wanted to provide all of the clues, in context. As some readers may be thinking, it is still under warranty. I live about three hours from the dealership, so would prefer not to make the trip if the cause and solution of the problem can be otherwise determined.