Help me figure out predict what happened with my bike?

To start. I have a honda shadow 1100.
recently did some carb work myself its the second time i did it.
i noticed the intake is a little rotten. I might need to get a new hose or two for the intake because it really isn't long enough.

so. I went for a ride today. Came home, left the bike out for like 3 hours. Went back out with carb clean and sprayed down some old fuel. I recently replaced the seals on the carbs.
i turned the bike on, and BOOM. Sounded like a gunshot.
and after that, my light, which used to only have the two options off or highbeams now has low beams and high beams with no off button?
so i took it for a quick spin
now one of the engine blocks sounds different.
now once it gets into higher RPM it sounds more like… I don't know a roar mixed with a motorcycle rather than just a motorcycle.
when i got back, i turned it off, cleaned some more gunk off the heart of the bike and tried to turn it back on only to find. My battery is dead.

battery is now charging.

what went wrong? Any ideas on where to start?

Added (1). the irony is the bike was working better than usual this week

It sounds like you backfired through the carb and either blew the intake rubber off one carb or the air cleaner to carb rubber as that too will have a profound affect.
Not sure about the button issue but the VT1100s have an issue with the stator to rectifier connection under the seat. Being too weak. Check the big connector in the bundle that has 3 yellow wires on each side and look for burning or heated condition. Eventually a stator or rectifier will go bad or one will and take out the other… Reason for dead battery. I don't believe the VT1100 has an OFF position for the headlight - just high and low. Headlight is always on.

I'm just excellent at predicting the past. You can bet on Secretariat winning the Triple Crown, for instance.

Don't really understand what happened… So you sprayed some carb cleaner all over the bike, then turned on the ignition. By the sounds of it a spark ignited the carb cleaner and you created a small explosion. That explosion either damaged the wiring to the lamp, or the (faulty) wiring was what caused the ignition. Your lamos working strangely suggest you have a short. Your exhaust sounds funny? (Don't really understand your description) - it's not unlikely that said explosion lossened the baffles. Like I say, I don't really understand the sequence of events but you should check the wiring harness and try not to over-use highly volatile petrochemical products on the bike.

I have a carb cleaner that specifically mentions never using it on any electrical components. Since it is highly volatile and flammable I would never use it and then immediately put a potential source of a spark close to it. I expect it would go BOOM if I did.

I wonder if that happened to you.

I would also expect a slightly rotten hose to allow carb cleaner through the damage and that too would be explosive if it was drawn into a carb instead of just air and fuel.

Fix the intake manifold gasket rubber… With a new one. It backfired into the carb. No big deal.
FYI Gasoline has more explosive power than carb cleaner.
You never heard the backfiring before because it goes into the air cleaner so is muffled… And rarely happens.

On my Honda. Many of the connector shells got old, brittle. When replaced, a pin would slip and be displaced. Connectors to fuse box just pressed in, they worked loose. Vibration could cause a problem like yours, then also cause it to mysteriously go away.