I hear you but breaking after 38 rides.. 4 hubs in one year at that rate thought a 6k bike would last longer. Some of my rides have been on a flat canal.
I think you can get the general gist of things from people's replies.
Think of it this way .. half the people complain "why do these bikes cost so much" .. it's basically because they're performance items. Most performance items require regular maintenance. It's not a £6000 sledge hammer. It has dozens of delicate and carefully engineered parts to keep the weight as low as possible whilst still providing the strength needed for normal use.
You say you've done 38 rides. Keep in mind that several of the parts on your bike will have 50 hour recommended service intervals, not to mention all the other regular checks you're supposed to perform.
You've shown the cassette wobbling around. We don't know if the cassette has just come loose and you've not noticed, or have noticed and ignored it and it's caused the damage you're now worried about.
It's a mountainbike. It's a precision machine which requires maintenance and checking over regularly if you want it to perform to it's best and most reliably. If something's loose and you ride it like that, it will damage something.
I'm not sure where you're coming from with the "some rides are on canals" .. you might do 37 rides plodding along and then 1 ride where you throw the bike down a mountain. What does that prove ?
Your comments seem to either suggest that you think it's either someone elses fault (like when your battery cover came off and that was Rob's fault for not reviewing the bike for long enough) or that maybe you're just not really into this and you're looking for excuses not to do it ? I'm not saying that's the case - but that's how it reads.
Mountain biking is an expensive hobby. It's also not a buy and forget hobby. It's a hobby where it's a good idea to learn as much as possible about the bike for your own piece of mind and safety. For instance, you've made a video about the noisy motor and now you think it's the hub ? Are you really saying you can't work out which one it is on your own ??? Even if you had to roll out the high tech fault finding equipment and say - take the chain off .... spin wheel .. spin cranks ... where is the noise coming from ?
Either way, I feel for you. We love our bikes and I hope you get this sorted and learn from the experience. At the same time, you literally have no idea what the problem is or how it was caused, so I don't think you're in any position to complain about Haibike or Yamaha. If the motor is at fault from water ingress - that's 100% on you. If it's something else, then it will be replaced and you join the unlucky minority who've had failed motors. Be that Yamaha, Bosch, Brose, Shimano - it's simple - they all have failures, they are not indestructible. Anything electronic or mechanical can fail.