This is usually one of two things, The charge port, this can easily be ruled out by being able to use the mouse wired. The battery, it may have degraded for various reasons however if the mouse indicates its charging when plugged in and when unplugged it dies, its most likely the battery is no longer able to hold a charge.

What you're describing is probably the hinge, these can break for a lot of reasons ( damage from a drop, bad design, wear and tear, etc.) When this happens the only course is to find a suitable replacement hinge and conduct a repair which may or may not be intensive depending on the model or on how damaged it is ( would need photos to know).

Valve Index Headset Head Strap $115 (apparently this comes with both speakers) Valve Index Headset Left Eye Tube Assembly $135 Valve Index Headset Right Eye Tube Assembly $135 Valve Index Headset Face Gasket $25 This would come to $ 410 (I used the pricing for the ones that came with tools you can probably save like $10-15 by just buying the part alone) Technically you can find cheaper parts from other sources however they may comprise in quality and may not be that great in the longer term. Only you can decide whether or not this is is worth it over buying a replacement. Looking at the guides replacing the minor stuff like the headstrap seems like a walk in the park however the lenses seem to be a more involved process in which you would want to be comfortable with before pursing this option. Valve Index Headset Eye Tube Replacement

You will need a replacement cable, you can buy these off of sites like eBay; however I personally prefer to get them off of other broken mice. I would follow this guide to see how to open the mouse: Razer Deathadder Elite Scroll Wheel Replacement

To be honest you got lucky being able to remove it out of the port, if not that port would've been unusable. Generally I would avoid using the dongle again as it is bound to break off again however I know mice like these do not have the ability to be used wired and would result in the mouse being junk. So here is what you could do (but i wouldn't do myself), If the shielding around the dongle broke off you could try and re-attach it back to the dongle then use a strong adhesive to try and bond the two halves together. Avoid getting any of it inside the part where the dongle would theoretically mate with the port this is as it would make plugging it in impossible. In addition to this I would buy a small USB-A extension cable in which you can permanently plug this dongle into, this would provide a safer way of plugging into different devices without risking the port. However as much as I hate to say this you are probably better of buying a new mouse from a more reputable brand such as Logitech in which you...

When this happens the most common cause is the battery just being dead, this can happen for a variety of reasons such as excess heat (being left in the sun) or just general use. It could also be the charging port however if you get led indication that the charger is working then you can probably rule that out. You can replace the battery but that may be a very involved process due to how tight and sealed these products usually are, However sometimes people have luck leaving devices like these on charge for a while for it to randomly come back to life but I wouldn't get your hopes up doing this.

While USB C is a standardized connector, the implementation of its spec may not. Some charging bricks or cables while may advertise higher may not be able to provide it to your specific device, I would try them on different devices so you can single out the issue. However first I would check in settings that you have fast charging enabled in the settings.

First I would check if your boot drive is being detected in the bios, you can do that on most computers during startup by pressing the delete key or F12 (Different systems use different keys you can probably google the one for you.) From there I would try to see if your boot drive is recognized by the system, if it isn't it may be the case that your drive may have failed which will need to be replaced. If it is recognized you may have to reinstall windows (or any other OS of your choice), you can do this by formatting an empty USB stick (8GB+ recommended) then creating an installation media from https://support.microsoft.com/en-us/windows/create-installation-media-for-windows-99a58364-8c02-206f-aa6f-40c3b507420d (this will result in any data from the drive being wiped)