Ender 3 print bed damage
your print surface is destroyed
So, you managed to rip off your print surface in the center. Happened to me too. the corners of my scraper were too sharp, cutting the surface. Another time I did pierce the surface with my nozzle. Damage happens. Replacement surfaces for the Ender3 start at about 5 bucks a piece. So get yourself some spares. Clean your bed before applying the new one.
Removal process
To properly remove a print from the bed, grab your srcaper blade and do the following:

sharpen the edge only on ONE side.
soften the corners, they should be slightly rouned.

Make sure the scraper is kept sharp.
When removing prints, be slow! Push the scraper against the bed with the bevel upwards. Apply careful pressure till the tip moves just a little. Move to a different spot till the blade slips under a little, then work the scraper left and right. You'll hear a sucking sound, that's the print coming free. It gets much easier if you let the bed cool down.
For very tall prints with a relatively small area, you might not need the scraper at all.
PETG has a tendency to stick too much with glass and fuse with PEI. We don't know if the Build-Tak clone Creality uses contains PEI. I suggest to grab  gluestick to add a safety layer for printing PETG.