It is very hard or even not assessable to defend yourself if the other player/infected is getting to close to you.

For long firearms it makes some kind of sense, but with a pistol it doesn't make sense to me. This could kill you in some buggy edge cases (like in this clip https://clips.twitch.tv/GenerousRoughLorisUnSane-TCXDCFS5nTs0UZbb ). If you go backwards into a corner, and you are out of stamina to perform a "F" melee weapon attack, you can't shoot anymore at all.
This whole "weapon-auto-lowering-feature" in close quarters is frustrating. Because the char is "raising - server is denying with some latency - lowering" experience feels very "unsatisfying".

Possible solutions:

• Firearm melee attack with "F" should be possible even without stamina (like a normal melee attack with a melee weapon)

and/or (which I would prefer)

• The player should be able to "hold" raised (at least a small arm like a pistol), no matter if in the meantime another player or infected is getting to close.