Greetings

To make vias-small holes in glass,there are basically 2 low cost options
micro particles blasting or diamond drilling
Diamond drilling is done at high speed 10000 rpm or so.
One may try an dremel tool however the run out can be a proplem .
We use an air driven motor the spindle for all practical purpose has no run out.
With a diamond drill it will take seconds to get 2 mm dia holes
With the micro particle scheme we use a mask and than blast.
Hope this gives you an idea what to expect.
Regards
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Dov