Zetsubo-high -noipx -novid -nocrashdialog -nojoy -noborder -threads 4 -useforcedmparms -noforcemaccel -noforcemspd -heapsize 4194304 -fullscreen -console +map_background preload_room +exec autoexec.cfg
jesus christ how horrifying
literally only three of those commands do anything you'd want (novid, nojoy, noborder), and you probably only need two. hell, some of them cancel each other out (noborder and fullscreen).
edit: here im just going to document it so people know in the future
-high increases TF2's thread priority, which should really not be an issue unless you've got a shitload of other applications open
-noipx just disables IPX networking which you don't use
-novid is actually relevant
-nocrashdialog is meant for srcds and does pretty much nothing for your client
-nojoy is really only useful if your game keeps enabling the gamepad and disabling mouse/keyboard (happens for some people), but apparently it doesn't even work anymore so YMMV
-noborder makes it so windowed mode is borderless fullscreen, if you're playing in actual fullscreen then this option does nothing
-threads forces TF2 to use a certain number of threads, this is very likely useless for you as TF2 automatically handles thread creation
-useforcedmparms -noforcemaccel -noforcemspd became irrelevant in 2011 when raw input was added
-heapsize was removed from the game in 2010, and even then, it never did what you thought it did. heapsize affects the size of the chunks of memory the game allocates over time, not how much memory it actually uses
-fullscreen is irrelevant because you can set this ingame
-console just opens the console when you start the game, it doesn't enable the console (there's an ingame option for that)
+map_background preload_room will launch preload_room, i assume you're doing this to preload. this can be moved to an autoexec line though, try:
map_background preload_room; wait 10; disconnect
+exec autoexec.cfg literally will make your autoexec exec twice, wtf. it already execs when you start your game. that's why it's called autoexec.