Glass bed on Ender 2 pro

I like the build-tak-like bed that came with my Ender 3 pro, however because I have a significant dip in the center of my bed it is impossible to level. I've tried shimming with sticky notes and that works OK. I think I've reached the end of life on the surface as I now have to put glue stick on it to get a reliable hold, and that glue then has to be washed off the parts. Many people seemed to like a glass bed so I thought I would try it, and ordered a Creality glass build plate. At least it is flat, but none of my filament will stick to it reliably without some glue stick. With the Glue stick added, parts have to be pried or hammered off, unless they are tall enough to give some leverage. I've tried water or alcohol, on the glued pieces, with little improvement. Many people suggest that their parts just pop off the glass as it cools, but I have had no such luck. I print with filaments.ca's "Econofil" the most, it works great for me on the non-glass surface. I also have Hello3d's silk and shining filaments, and some other "standard pla" which is supposed to be based on Ingeo 4043D ... none of this sticks without glue, and it sticks way too well with glue. I print at 200/60 for most pla, and 220/60 for the 4043D. The first layer of filament lays done nicely on the bare glass, and wont rub off, but if you get your nail under it it pops up and the whole things will peel off with little pressure. The result is that if any small corner lifts a tiny bit as it is laid down, the whole thing will eventually come off. Also once it gets a bit higher the leverage of the nozzle moving around will tip it over. With the glue on the glass it is hard to peel up even a single line of filament as is stuck down hard and shows a white residue where you've peeled it off. I've already bought a new Creality magnetic build surface to replace my old one, but I still wonder why I cannot replicate other's results on glass. For extra fun, it seems the polarity of the magnetism of my new magnetic bed is off by 90 degrees so I need to either cut the convenient lift-handle off the new plate, or peel off and replace my entire magnetic surface ... does anybody know, if the direction of magnetism is just random? Do I have a 50% chance of having to do this every time I buy a new one? In that case I may have to buy several at once so I can use the same-way magnetized ones first ... ugh. Thanks for any tips for sticking to glass!

You seem to know what you're doing.
so i suspect you've already tried z-offset and slowing down the first layer.

And given that creality only ever use the cheapest components - I'd go with 'random' magnetism until proved otherwise. :-)

An alternative would be a cheap sheet of PEI.
You don't have to use the self adhesive aspect, and could simply use it with some metal clips.

I haven't done anything with z-offset, but is that any different than just tightening the leveling screws? I found with glass that I need the nozzle to scratch a divot into a post-it note held on the glass to be close enough to stick at all. Any looser or tighter and it wouldn't stick, it would usually curl up and get stuck to the nozzle and then there is no hope. This is definitely closer to the bed surface than with the Creality build-tak surface. I usually print with the default Cura Ender-3 profile which is at 50mm/s and 50% so 25mm/s for the first layer, should I try even slower than that?

With the ender 3 i found it difficult to print anything direct onto the glass plate even with adhesion aids. In the end I ended up using a thin sheet of Tufnol sanded to remove the glossy surface clipped on top of the glass bed. A smear of PVA glue stick and it works every time for PLA and PET-G. For ABS a coating of ABS milk (10% abs filament in Acetone) works the magic for the filament brands I use but there are brands that I have failed to print !!!!..
As you know the leveling settings are crucial in my case with the Ender 3 about 0.075mm is right and about what you get with a piece of 80grm printer paper or better still get a piece of metal shim stock. Here in UK shim stock can be obtained on EBay from model makers suppliers mostly it seems to be sold in thousandths of an inch 3thou is right 0.076mm.

Put the Build plate in the freezer for a few the print will pop right off.