92 Longbed,
If you have worked on vehicles long enough, you have been in a pain funnel like yourself. (Multiple issues/complex fix or one fix breaks something else.) So I feel for you.
Lets recap your work -
1) Glow plugs all are tested and good.
2) New glow plug controller. - Appears to be working but smoking a little. (Smoke could be from dirt/grease that was on your hands or the cables. Just turn on and look, you should be able to see what is smoking.)
3) New battery - Starter working correctly now, vehicle turns over well.
4) Prior to starter issue, truck would take multiple attempts to start even when warm. Once running it ran without issue.
Now your truck will turn over but it will not start, but you see grey smoke. (Usually partially burned diesel.) A common issue when you have air in your fuel lines. (Pre or post fuel filter.)
Some ideas to look at.
1) I would first confirm the glow plugs are working. (Confirm do not assume.) It can be hard to start a cold truck without glow plugs heating up.
2) If the glow plugs are working then I would look at a fuel issue. I like to think of the fuel filter as the separating line. Separating fuel delivery and fuel return.
a) It's very common that the injector return line system is leaking. It causes the diesel to leave the system and go back to the tank, leaving air in its place. Then hard starting and when it does grey smoke. One common sign is you see when this the case is wetness around the injector or return lines.(Where the diesel can leak out and the air can leak in when shut off.) Or diesel collecting dust/dirt around the injector. If you have not done so in some time, I would just redo the return lines, caps, and O-rings. Your supply house should be able to order you the kit for $40-100 depending on brand. There are two different kits based on age, so make sure to get the right kit. When these leak, it often causes the engine to not start right up, rather crank and crank, and crank and then V-room. The fuel has to push the air out and reprime the system. So 2,3,4,5 times later the engine starts, idles rough or runs up the RPM, and generally blows out grey/white smoke for a brief period. You mentioned that was the issue before your starting issue came up. You likely killed a older and marginal battery by doing all that starting. (Don't feel bad, I went 2 months with my glow plug system not working before I got around to fixing it.)
b) Fuel supply issue which can be tricky but here are some causes. Clogged fuel filter. Bad lift pump. Broken fuel line. Clog in fuel tank, or too little diesel in tank. Broken tank transfer system, these often go bad and get stuck in between switch positions. So hard to say where to start here, but there are many threads on each one. Perhaps start with a new fuel filter and check the lift pump is pumping out diesel during starting. (If its pumping, then likely its post filter.)
c) IP timing can also be a issue. When your timing is off, your truck may not start as easily as it should. However hard to do the timing till it is running.
d) Make sure your cold engine IP advance is working. It uses a coolant sensor to turn on or off power, when cold it will advance the IP (So I have heard.) and then holds the idle higher till your truck warms up. You would know if this was working before because your truck would idle higher when cold. Use a test light or volt meter to see if you have power at the IP pump as your engine is cold currently.
e) Also the diesel shut off is on the top of the IP pump. Power to it and it allows fuel and thus the motor to start and run. No power, no fuel, and engine shuts off stays off. You said you have white smoke so likely this is working as diesel is getting into the engine. Again don't assume, test and confirm. It could be partially working.
So you need this truck running. You might want to loosen your injector lines at the injectors and bleed the system. Then immediately after tightening the injector lines, with the glow plugs working, try to start the truck. If it starts then you at least can move the truck till you have time to repair it. Once you shut it off and the diesel can bleed off, it will be hard to start again.
Good luck and let us know what you find.