This is what I think. You told me you were relatively new to Inventor and CAD in general. The templates as you said were created by someone else and looking at the fact that they are .dwg files and probably should be .ipt , although some could make the argument for either, my best guess is that these were created using Autocad and brought into Inventor to be used as templates. What I think you are seeing are in Autocad world called "Nodes" and because they seemed to be embedded, I could not remove them either. So, given all of that, here is my suggestion.
Using the out of the box "Standard.idw" format, open it up and
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in the format of .idw
Then do this,
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Now, it will come in with it's standard titleblock. Delete it by doing below.
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Then to edit the imbedded titleblock in the format, do below.
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Now, while you have your current one open in another window (you will be toggling back and forth between the two)
window and copy as I show below, from your old one,
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You can do this repeatedly to get all of your pertinent information from the old to the new until it is completed.
Don't forget to save it as you do this process and keep it as an .idw When you are done, make sure this template is in the folder where ever you are pathed to for your templates. I hope this all makes some sense.
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Windows 10 x64 -16GB Ram
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Inventor Pro 2021
Best Regards,
Scott McFadden
(Colossians 3:23-25)