2018 CRF250L Rally won't start - dropped in water

I was trail riding and dropped my bike in some water on a dirt road. Now it won't start. I'm looking for some directions on how to diagnose.

1. when turn key on, display comes up. Horn works and lights work.
2. when I try and start the engine, the entire LCD display goes dead. the engine doesn't turn over at all. It's like the battery got drained. battery is dead for about 10-15 seconds. During this time, nothing works on the bike (ie lights, horn).
4. after a bit of time, battery comes back and display works again. But if try and start, same as #2 (display goes dead).

things I've tried

1. using a different battery (from my other motorcycle). same issue. so don't believe its the battery
2. checked all the fuses. they are fine
3. unscrewed the ignition switch and cleaned out with compressed air. made no difference

Not really sure what to check next. I think I should check the starter and the starter relay. I've tried looking on YouTube but most videos remove these from the bike to test. I believe the starter on the 250L is buried and not easy to remove. Any advice on how to test? Or are there other things I need to check first.

thanks in advance