It sounds like your bed may be out of level if you're consistently not sticking at the back.
When I re-level my bed, I follow Ultimaker's instructions with the business card to get me in the rough area. Next, I start a print that is about 8" x 8" with a four line skirt, and run it very slow, like 20mm/s. I watch my first layer. I like it pretty firmly pressed into the glass. Some people like it smashed hard, I learned that's a little too much. While the skirt is printing, I adjust my three level screws until I see that first layer where I want it. Next, I cancel the print and start it again to make sure it ended up consistent and how I like. Then I cancel the print and get printing whatever I want.
With a well leveled bed and good first layer, print adhesion should never be an issue short of getting oil or contaminants on the build plate. I can't remember the last time I printed a birds nest right off the glass. Also, are you setting a lower first layer speed? I know Cura slows it down automatically, I like to lay that first layer down just as slow as I can tolerate.
I think this post might cover all the issues you have atm
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