I’m sorry, we really can’t answer this question, (or any of the four or five like it we’ve gotten.) This doesn’t give us enough information to make that call.
What your character’s doing will have a role on what kind of armor they’ll wear. Heavy infantry would field full plate, but for scouts, that’s just going to work against them.
I hate the “light armor = mobility” crap, when it comes to fantasy armor, but that’s because it’s usually applied incorrectly. Mobility is about getting in, seeing what’s going on, and getting out, without dying horribly, not bouncing around in combat.
Chain is usually what would be available for front line combat, because slabs of iron or steel were expensive, but if your character’s a mercenary, they’ll probably go with whatever they can afford.
The other issue is “when”, or more specifically, what’s in your setting. Armor isn’t some monolithic technology. Even games like D&D have a bad habit of including armor that’s anachronistic to the setting. If you have fantasy materials to work with, that will open new avenues of armor technology. If you don’t, it’s important to remember that armor has constantly been evolving from the beginning of human history to today.
I mean, the Kevlar armor we field today is substantially stronger than the Kevlar produced ten years ago. So, asking, “what’s the best armor for my character,” is a product of that exact moment in history, combined with when and where your character exists.