My first camera, what should i chose?

I'll start by saying my budget is 300€ and I am obviously only looking on the used market. I mostly plan on shooting portraits and maybe some street photography too. Low light capabilities aren't needed but would be a bit helpful sometimes. I do not care about video capabilities.

With that being said what I'm currently looking at is the R100 or something older like the 6D. Either way for now I'm only planning to use them with the kit lens, at least until I start to get a bit more into photography.

The R100 I found at 300€ while i managed to find a 6D at around 250€ which would also let me buy something like a 50mm f/1.8 EF lens (used obviously).

My main reason for having no idea about what to pick is the AF. From what i found when I looked into it the AF on the R100 is much better but I don't know how much that would benefit me for what type of pictures I'm trying to take or if the bad AF on the 6D would give me that much of a headache

Would be happy to hear some opinions on what I should chose between the two or maybe even other models that you would recommend.