Why not "Ich Befühle besser" ?

Why is "Ich bin besser" incorrect?

Is "Geht es mir besser" wrong, or not? When I hover, that's what it tells me the translation is.. but when I translated it as that, it it said it's wrong? I feel like it should be right but I kind of struggle with word order.

"Mir ist besser." sounds strange to me. I would rather say "Ich fühle mich besser." "Ich bin besser." means that e.g. you have compared to another person a better ability of sth., e.g. calculating: "Ich bin besser im Rechnen als sie." If you talk about state of health, you use "Mir ist..." or "Ich fühle mich...". In the first version, you normally use adjectives in the positive (the version which you find in a dictionary); in the second you can also use comparative (besser/schlechter etc.)

"I feel better" is translated to "Mir geht es besser" but "he feels better" is translated to "Es geht ihm besser". Why did the Es change place?

So, if I translate this sentence word-for-word it would look like "me is better", like George of the Jungle speech. If I want to say "we feel better" would I write "Uns sind besser" or "Uns ist besser"?

Mir geht schlecht