Are there any cheats for campaign mode? I tried using one found in the instant action menu and It didnt seem to come up when I played the campaign. I need cheats because the last few parts of the campaign are pretty close to impossible.

They should work. At least they did in 1.1 (current gog version are backport from MP Update#2 with exe from 1.1).
Sometimes they randomly stop working. In instant action. A bit often in campaign and galaxy conquer.

But usually they work in any SP mode.
There is also cheat for mission select. Hmm and probably it can be saved stored to save file. Use this menu if load game keep not working.

There is cheat trainer exe that additionally (or alternatively) can change Reinforcements quantity. There is major Ai issue even on Hard AI (Hard difficulty are easier... Looks like). Many bits just go eomewhere where they die. Or ignore enemy.
It ismore often happned in campaign mode cause they use standard map waypoints. It is more noticable and more major big in campaign cause enemy AI have no limit in quantity.

Somehow they die very fast in space missions too. And some mission add very few of them after next goal achieve. Also some space missions have very few bots on player side.