It sounds like bed adhesion might have got worse, perhaps you have touched the print surface with your fingers while removing prints? You could try removing the plate and washing it with warm water and soap. Some people use IPA but if you do then you need to make sure you really wipe it clean before it evaporates, otherwise the dissolved fats will stay on the bed. If your bed has some kind of anti-stick coating I think there’s also a risk that you damage if you use stronger solvents.

As for warping in general it could be an indication that your flow rate is exceeding your melting capacity. If you have an all metal hotend you could try printing at higher temp, if not then try reducing print speed instead.