Upgrade suggestions from EOS Rebel T8i

[natephotos]

Hello all, currently I’ve been using my Canon T8i for almost two years and I’m happy with it but I know eventually I will want to upgrade. I currently shoot rock climbing outdoors and also indoors(which doesn’t have great lighting at times) I switch between an EF-50mm f1.8, EFS-24 f2.8, and an EF-75-300 f4. I’d eventually like to get into Motorsport photography so I’d like to find something that will be good for both my rock climbing and Motorsport photography; maybe some portrait photography as well. Thanks for any suggestions and advice! 

[Tronhard]

Hi and welcome.

To clarify. Do you want to upgrade the camera or lens or both right now?

If you do plan an upcoming update of any kind we would be helped by knowing a budget value and what that has to covet.

[natephotos]

Just camera for now. Maybe a budget of $1500 or so 

[Tronhard]

For your requirements:
Ability to locate people for rock climbing but also for motor sports in the future, I would recommend the Canon EOS R6 series or the R8.  These have the benefits of Face and Eye detection and tracking, and can lock onto faces in cars, which I suspect might be particularly helpful for motorsport aspirations.  The R6 series (but not the R8) have In Body Image Stabilization, which is good for shooting hand-held and tracking.  All three share the same full-frame sensor that is particularly good in low light.

You can use  your EF lenses on R-series bodies via a Canon EF-RF adapter, and these work extremely well.
HOWEVER, you would have to consider abandoning the EF-S 24mm lens as it will not function well with a FF sensor - it cannot use the whole area of a FF sensor and thus reduce your pixel capacity significantly.  
I would consider selling your T8i along with the EF-S lens to help fund the purchase of a  R6 and one or more RF lenses.
While the EF 75-300 will work with the R-series bodies, it is considered one of Canon's poorest optics and does not itself have image stabilization. If you like you can continue to use it but I would recommend saving up for an RF lens that could cover the same range - my pick would be the RF 100-400 USM, or the RF 24-240 USM, which are both excellent optics.  There is not such a hurry if you are not quite ready to do motorsport shooting.
Within your budget you could get one of these, especially good value as refurb units:
EOS R8 refurbished, body only 
EOS R6 Refurbished, body only 
As regards lenses:
Refurbished RF 100-400 IS USM 
New RF 50mm f/1.8 USM 
New RF 24-240 IS USM 

[natephotos]

Trevor, thanks for your advice! It’s very insightful and I appreciate it. I will definitely look into the R6!! 

[natephotos]

Thoughts on a 6d?

[rs-eos]

An EOS 6D is a DSLR.  It will be difficult to get support for DSLRs (especially the older ones like the 6D).

Having said that, it was a very good camera.  I owned it.  Though I did not like its very limited number of focusing points.

[Tronhard]

The EOS 6D is an old DSLR (released in 2012), and for its time was ok, but it has definitely aged.  It has an old sensor, old processor, few focus points, not IBIS, no Face Tracking.  It is no longer serviced, as far as I know.
I hope you get my point...
I honestly and thoroughly evaluated your options based on what you say you do, and what one would expect for performance benefits for such activities - unless you offer different needs, I shall stick with my suggestions.

[natephotos]

Just thought I’d get an opinion of it and some thoughts. Thank you for everything! R6 is definitely the way to go!