First, lenses are more important than the body. Figure out what lenses you will need to shoot your interests and then buy the lenses that match.
For example, a very affordable lens for portraits is the Canon 50mm f 1.8. New it is only $125 US. Nikon has an equivalent.
Next, get the body that works with those lenses and used is a great way to go. For example a used Canon 5D Mark II is a professional grade full frame. Yes, it is at least ten years old but it will still be capable taking the same spectacular photos today that it took back then... for only a few hundred dollars.
Mark sure you know the difference between full frame and crop sensor. One is not better than the other, they are simply different tools. Most consumer grade cameras are crop sensor and most higher end cameras are full frame.
I have a T7i that I got for business travel along with a Tamron 18-400mm super zoom. Very capable, very flexible. Certainly not professional grade but a good all-in-one way to start.
Sony, Canon, Nikon, Lumix... they are all capable. Get the best lenses you can afford that fit what you want to shoot and match them to the brand/body.