The bed should take about ten minutes to reach temp and the nozzle should take about 5 or less. If you are not running stock firmware it is always best to heat the bed first then the nozzle. You dont want the nozzle to set at full temp with filament in it for more than a few minutes. This can make the filament inside harden and cause clogs and jams.
As for your bed it sounds like yours is like most and warped. The only thing you can do is go to a local glass shop and have them cut you a couple of 3mm thick pieces of tempered glass the same size as the stock glass. Once you get it loosen the screws enough to mount the new glass on top of the stock and tighten the clips back down. Adjust your z to account for the extra 3mm and you should be near level now. If not then one or both of your X rods are bent.
Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.