Kohaku

As a former spy main with 390 hours of spy, I would use the stock invis with the letranger and the kunai. I would use the letranger and the cloak and dagger with the spycicle for silent attacks and make the enemy paranoid so they get distracted enough to kill spies rather than do the objective. I would use the dr if you are a type of spy that loves to be aggressive, and is good at trickstabs (I use the dr but I am a medium level trickstabber) Remember to equip the amby or the stock revolver depends on the situations, and stock knife if there are too many pyros, and kunai if the situation is calm, and if you like, use the big earner if you feel like the dr is very slowly regenerating and you need it more often.

It might be unbinded by mistake, so try resetting ur binds to default, it in the settings under the keyboard section, then if you have any custom binds then rebind them. I feel like this is the only solution. If you turn off TF2 and turn it back on and it unbinded itself, then there might be some conflict in commands, maybe a config can be the purpose, so delete or edit the config.

The command for binding is bind "the key" "kill or explode" either choose kill or explode and if the command didn't work then switches places between the key and command.

Maybe check if you can find any config files to fix the game's texture quality and graphics. Im basing by information of my experiences in TF2 config scripting.