I couldn't find any information on that specific model.

There seem to be a lot of different setup codes that are variations of the basic code set used by Grundig TV's (so I can't suggest any "best" setup code to retry), plus I think there are some Grundig TV's using code sets that aren't in that group at all.

I think your remote can learn the signals for the Grundig TV. It may not have enough learning memory to learn all of them. But I interpret "cannot get the OFA (4 in 1) to operate the Grundig TV" as meaning no functions work.

If you have any functions working, either by built-in setup code or by learning, you should say so. That makes a big difference.

If you have no functions working by learning, you should review the process you're using to learn. You're probably doing something wrong.