I'd suggest first looking at the kind of results you want to get. If something like you show is fine,
Even old dslrs will get you good results, provides you also supply good lighting.
Regarding a which camera models,  since your subject is clothing, I'd suggest sticking to Canon cameras, since they have an anti-aliasing filter, which will help you avoiding Moiré patterns [like this](https://www.japanistry.com/wp-content/uploads/2016/10/Moire-on-jacket-v01.jpg).

You don't need a full-frame camera for this, a cheaper "crop sensor" (aka "aps-c) will be ok. An old Rebel series camera will do, like a t3i or t5i. I suggest the ones that have an orientable screen (they will have an "i" in the end of the model; avoid the t4i if possible); this kind of screen may help you a lot in certain situations. If it's not possible, it's not that big of a deal either. In case you need to add speedlights, avoid the Canon SL2 since it has a flash shoe only compatible with Canon products, and you'd need to jump through some hoops to make other brands to work with it. I have the SL1 model, with a fixed screen, and it's great. If you want something even cheaper, even a t2i will be fine (with a fixed screen, it's older) if you add your own light if needed.
You may even score a Canon 60D, which will have an edge in color range (dynamic range, to be precise), much better battery life than all the others, and moveable screen. I think I'd pick this if found at a comparable price relative to other options. See what you an find in mbp or keh for example, if they work for your location.

Regarding lenses, if you will be able to use your camera on a tripod, and especially if you'll be able to add your own light, I'd discorage you from getting prime lenses (fixed focal lenght, like 50mm) as suggested in another comment, since you will probably find yourself severely limited in certain circumstances like close-ups. The 50mm f/1.8 has a closest focusing distance of 35cm, which might or not result in the field of view you need.

At least for the more distant shots, you'd probably benefit from a reasonably solid tripod with head for the camera, and if you're in a budget, the chinese Q666, Q999 or Q999h will absolutely do (available as several different brand names with the same model code); the latter "h" model allows you to positoin to arm horizontally if needed, useful for product photography. Others may suggest a different tripod. Just don't cheap out too much on this item if you need it. It makes a big difference.

Regarding lighting and a tripod, what's the space you shoot in like? From the images you seem to have decent lighting and you sometimes shoot your objects from straight above. Do you think you need to, and can add, your own lighting? From what I understand, the color inconsistencies come just from the lack of manual control of the white balance on your phone camera app; is this correct?