How long for primary fermentation on a Pilsner

Hello, I am new to homebrewing. I got inspired to try to make a pilsner urquell "clone," my third batch of beer. I used both grain and extract. I also used a lager yeast.

I have the beer in my primary fermenter, where it has been for nearly 4 weeks. It still shows signs of fermenting (bubbling in the airlock).
The instructions said to ferment in temperatures between 32 to 50 degrees.
My garage stays about 42-28 degrees and that is where I have my fermenter.

The O.G. was pretty high, so I would think there is a lot starch for that yeast to munch on.

How long should I let it go? If I move it to the secondary, do I risk anything?

Any advice is appreciated.
Thank you

I like to ferment my lagers around 50, and that generally takes 10 days to 14 days to ferment out. Then, it's good to check the SG and check for two things- to see if it's fermented about 75% of the way, and to taste for diacetyl. If you taste any hint, or even a hint of a hint of diacetyl, you need to do a diacetyl rest. Diacetyl in abundance tastes like butterscotch or buttered popcorn, but it small doses, it may simply feel like an oiliness or slickness on the tongue. If you taste diacetyl, or even if you don't but you want to be sure, you do a diacetyl rest while the lager is still on the yeast cake, and just before fermentation is completely finished. That's where that 75% done figure comes from. I like to do a d-rest at about 1.020 or so. You bring it up to 60-68 degrees for 24-48 hours, so that the yeast can clean up any diacetyl before you rack and begin lagering.

A diacetyl rest isn't always needed- it depends on a variety of factors like yeast healthy, size of starter, pitching temperature, the strain of yeast, etc. Some strains produce very little diacetyl and simply keeping the lager in primary for 3-4 weeks will get rid of it. Some strains are a diacetyl factory, and are more likely to need a rest.

After the diacetyl rest, you can rack the beer to secondary and then begin reducing the temperature to lagering temperatures.