Large flat parts can irritatingly be quite prone to warping. There are a bunch of tips, skirts and brims help. Preventing air currents helps, the plastic wants to shrink as it cools. Not much, but enough to pop it loose sometimes. This is somewhat complicated, as the heat from the bed in an enclosed printer can cause heat creep, which expands PLA filament as it comes into the extruder and blocks it up. It's a bit of a balancing act. Turning up the bed temp can help, but too much is also bad. I also like to disable the part fan for the first few layers.
For Bambu users...
If you have an aux fan, I know the X series do, not sure about P. Turn it down/off in the filament profile. You can also turn down the chamber fan, but you have to modify the gcode in the filament profile. I like having it ramp up with layers, so it's low at the start, but gets going later. I don't go above about 80% usually. It keeps the worst of the noise from the fan down while still venting to help keep internal temp reasonable.
Cool plate, I'm not sure what it is, but it seems a bit like buildtak. It's not bad, and a bit underrated. Keep in mind that the glue is more about releasing the part at the end. Oddly, it does help a little with sticking down as well. lol. One upside to the cool plate is that you can run fully enclosed without worrying about heat creep. Try using the minimum amount of glue. Give it a wash every once in a while.
High temp plate is smooth PEI. A nice surface. I use it on some of my other machines, Bambu's seems pretty standard. Nice to have around when you want a smooth bottom surface and the cool plate doesn't work for the filament etc.. PLA will let go with low force. PETG can become near welded if you aren't careful. Using a small amount of glue helps a lot with PETG.
Textured PEI plate. Probably my favorite, it's stupidly versatile, and I usually like the texture. It can throw off dimensions a little, so if you need high accuracy it might not be the best option. In practice, designs usually have more than enough clearance to absorb it. PLA will let go a little easy if you don't keep it clean. Dish soap and water, NOT alcohol. The claim out there is that the alcohol dissolves the oils and deposits some of them in the valleys on the plate, while the soap breaks it up and washes it out. No idea how true that is, but the advice works. PLA will hold once you get it right, until it cools. Then the PLA almost always self-releases. PETG works great on it, almost too well unless you have warp prone parts. A small amount of glue stick can help, but you can usually control it by turning down the plate temp a little, and the extrusion temp for the first layer. Though I will say when you get the PETG temps just right, it's stupidly satisfying to peel a large print off.
Reading that, maybe I should print less for a bit.... nawww...
