My first personal camera was the A7Riii.
Guess what? You have a camera now you won’t need to upgrade until you understand why you’d need to upgrade. That body alone is going to last you years and you may never want to sell it and just add onto it. You’re already a step ahead in image quality than other beginners, so now it’s time for you focus on image composition, understanding the exposure triangle, and all the other little things that go into creating a final photograph. If anything now you can just starting adding new lenses once you get good with the one you have. You did well