Plutonium

Looks like this can be disabled by running the following command:

seta aim_automelee_lunge_only_forward "1"

With the latest update (r4811), knifing zombies seemed to get a lot worse. Now, whether you're playing on controller or KBM, when you go to knife a zombie it sucks you in if you're within like 5 feet of a zombie (like OG knife lunging but without the animation), even while crouching or walking backward. Is there a way to turn this off/get around this, or just hope for a revert in the next update?

Only thing I can think of is making sure to have the underscore in "sv_cheats 1", other than that maybe try reinstalling
Nobody I've talked has ever run into the issue of it just straight up not working before so not really sure what the problem could be

Could try with "/sv_cheats 1" but that shouldn't make a difference on BO1/2

Are you opening the console with the tilde key and typing the commands in there?
I know that whenever you try to enter in commands without doing "sv_cheats 1" you get the "Cheats are not enabled on this server" message, but I've never had an issue with getting that command to work properly (solo or private match)

Also, some of the commands will show you their current value if you type the command without adding a value, so if you type "sv_cheats" then it should show you a 1 or a 0 next to it indicating what its value currently is

For example:

So you can actually just launch the map as normal (without loading any mods) and then use the following commands:
sv_cheats 1 (host has to do this, this enables cheats/console commands)
god
noclip
cg_draw2d 0