Bed is leveled and not warped but still uneven printing? I have the Creality CR-10S. I replaced the glass it originally came with as it was warped and I wasn't getting any material out on 2 of the sides.
I switched to a PEI sheet and got the same results after only a few prints.
I then switched to a mirror I had cut previously, and it worked for maybe 2 days. I scrapped a print off that warped, and then the leveling was off on that. My gantry is level, my beds aren't warped, I'm leveling it to allow a standard piece of paper to have friction by the head. It's either to close and no filament is extruded or it doesn't stick at all and drags filament everywhere. If I can get good extrusion on one side, it's horrible off on the other or all corners.
Note that I have checked my gantry and it is straight as well and my the bed. Not sure what issues I have left.
Be sure that you have no previous bed meshes saved and automatically applied: use the commands M502, M500.
Once you have done that, try this technique:

                
            
It's about using a ruler to detect areas which are lower, and then use stickers below the glass to thicken those areas only, resulting in a much flatter surface.
If you don't want to use the blue tape (which will worsen the heat transfer, but not so much after all) you could use 0.3 mm silicone thermal tape, which is more heat conductive but it's also quite thicker than blue tape.
This other alternative consists of flattening the plate itself, but it's inevitably performed when cold, while the tape technique above can be performed at the desired temperature (since the warping may not be constant).