Im not a photographer.
I have a 2000D Rebel T7. I bought it because I didn't know the whole Canon line up and what not. I know guns.
It was a good price. Got it to take pics of products for business, something better than a phone.
But is it good enough for everything? By everything, I mean I'm not going into a professional business line of work.
For myself and family, to take good, or decent pics. I haven't gotten to take the 2000D out yet due to time...mainly indoor tent pics at the moment.

Am I limiting myself outside of the profession soul sucking realm of snapping pics and editing them?

I recently found a decent price on a Mk5D IV. And I already have a 24-70 f2.8 II lens....

Do you have money enough for your purchase?

If so, then fuck the haters, buy what you want.

I shoot with FF and APS-C.  IMHO there's nothing wrong with APS-C.  Shoot what you want, and enjoy.

Do you like to photograph things that are far away?  Then go crop sensor.

Do you like wide panoramas, landscapes, or close up subjects?  Go full frame.

Keep in mind that full-frame lenses should work on crop bodies, but the inverse is not true.

Full frame lenses are going to be more expensive that crop lenses (more glass, more materials).

Now that I've said all that, for the casual photographer, or even the professional amateur, there's not a lot of noticeable difference.  I go crop because I like to shoot a lot of distant subjects, but I've never really felt limited for landscapes and close-ups; just have to get the appropriate lens.

I'd like to do both. Looking for more versatility with quality.
I have the 18-55 that came with the 2000D, and an 18-135 IS USM, and a 24-70 2.5 II USM
7D MK II a good safe choice? Or 6D MK II? Kind of leaning towards the 7D as I already have 2 EF-S lenses

Get one.

There, decision is made.

Fiinneeeeee..... 7D Mk II ordered

7DII is a decent camera.  It was my airshow rig along with the 100-400LmkII.

The full frame line is better at "art" & product photography.
The crop sensor cameras tend to have a faster fps rate, useful for shooting action, sports, wildlife, etc.
The Canon line I'm speaking of.

They each have their purpose & place.
Mirrorless Canon line (that I've experienced) can really struggle to get a focus lock in low light/low contrast scenes. Just in case you were pondering that too.

I have an original model EOS 5d, full frame sensor. It makes lovely images. It has dust issues (supposedly solved for mk2 & above). I'm fond of the full frames, added an EOS 6d to my line up last year.

I think you just need to think about what you want to do with your camera.

Not a bad decision. I should have read further before posting.
I think that will suit your purpose well.
Until you decide you can't live without an EOS 1dX.

as much as I liked my D7500 crop sensor camera, my D800 (just sold it) and D750 full framers were "that much better in image quality" that I sold it.

the size of the sensor matters.

I can use crop lenses on my FF Sony.  

I noticed you already ordered but I am going to toss out my theory for anyone else that may be in your situation. This is just my opinion and not law so take it with a grain of salt.

This decision comes down to budget and end usage.  If your budget is tight you can get the crop sensor body and to cover the crop you can just get a little wider that your typical 28mm lens and then if you like to shoot wildlife and such you dont have to cash in your 401K to pay for long glass.

If you can aford the full frame bodies by all means go for it. If you like to the milky way or landscapes as well as close up product photography this may be the choice for you. You wont lose that wide angle capability, but you will comprimise on the long end and have to make up for it with teleconverters and longer glass. and we all know longer glass gets spendy really fast

In the end get what fits your needs and dont sweat the sensor size. My little crop sensor 10MP  has had images cropped and printed at 20X30 and they turned out amazing. Most people  will never use their cameras for anything more than internet sharing and my moms flip phone can handle that task. A majority of the rest of those people will most likely never pring much more than 8X10 and pretty much any smart phone is quite capable of that task today.

Yep so true. If I were a professional, ie anyone making a living or getting paid for my work, I would definitely go with a FX camera, no debate. The photos in FX over DX cameras are way clearer at the equivalent ISOs. But then you do have to consider the cost, weight, size. If you are a backpacker, do you really want to lug a FX camera and the requisite lenses around? Those questions only each individual can answer

As for myself, I do photography at the local HS stage plays and concerts, so I need gear that is fairly obtrusiveness, but good performance at the low-light stage lighting conditions. And of course, I need a noiseless shutter when especially when taking photos of a chamber orchestra ensemble recital inside a classroom with about 50 people.

I recently upgraged from a 1" sensor Sony RX10-4 to a DX Sony A6600 mirrorless. One reason for the upgrade is the fact that the A6600 has SotA 5-axis IBIS, my RX10 has only 2-axis, and A6600 has faster focusing in low light conditions. So far, the A6600 has been great, I am getting fewer out-of-focus and blurred photos due to focusing.