EF 100-400mm Draining EOS M50 Battery? Future Camera Advice.

[Far-Out-Dude]

My battery on my Canon eos M50 seems to be draining very quickly as of late, I have two that are factory batteries and one that is a Vivatar My old lens (Canon EF 70-300mm f/4-5.6 IS II USM) had an led display on it that would drain the battery if not turned off but I do not see that on my Canon EF 100-400mm f/4.5-5.6L IS II USM Lens. The Camera body was recently serviced so I am wondering if it is something on the lens I may have missed? I have been using this lens since roughly April of this year so I do not see it being the lens but I am grasping at straws.

Also quick questions I am looking to upgrade to a RF body in April and was wondering what the difference will be in batteries, memory cards and I know I will have to get an adapter to use my EF/EFS lenses on that body but can't seem to find one, can anyone give me some information on that please? Thank you very much for your time and have a great night or whatever time of the day it is there where you are.

[Far-Out-Dude]

I always turn the camera off, are you say the continuous autofocus works even when the camera if off?

[Far-Out-Dude]

Hoping it is lower when I think I will have the money which is April, I do not have the money at this time.

[Far-Out-Dude]

That would be nice. I think I am seeing a joke there about the auto focus. When I shoot landscape it is always in manual mode, when shooting certain wildlife it is in AF because of visions problems and this time of year I shoot wildlife so AF it is. Truly wish it were not but if say I want to take a picture of a bird in flight if I have on my glasses that I can see the bird with I can't see my screen to see if the bird is even there and the reverse is true with my up close glasses. I hate it, bifocals make me very sick, hurt my eyes and made me fall down the stairs more than once. I do hope that price goes down, I would love to have that image quality.