Second on the glass print bed. You can put it right on top of the existing bed and fasten it with binder clips. If it's thick enough it will span any flaws in the existing bed and be nearly perfectly flat so you have a consistent platform to level instead of dips and waves.
Just adjust the z stop, and then print single layer leveling prints and adjust the bed slowly while it prints. The biggest things to watch for are where it prints too thin, it will look squeezed out, and where it isn't close enough it won't stick. It seems like a lot of work but after a few runs it starts to look better. Doing other simpler leveling test prints are frustrating because all you see is the end result.
Another thing that I've run into that resulted in leveling issues is if your z heights are different from one side to the other. It's not obvious, but if the z screw of the left is different than the right, you can level all day but it will still try lifting on one side. Run the zaxis up to about 20mm on the left and then move the head to the right and check the height there. A hiccup or crash in the past could have gotten this out of line, but you can manually bring them back to square by manually turning the screw and get things back parallel.
Last thing that really messes with things when you're troubleshooting and then abandoning the printer for awhile is filament getting wet. You can get things dead on, but if the filament has been unprotected for a few days, the slight swelling will fight you when you're already frustrated.
Then, the last thing is measuring extrusion. Raise the head up like 100 mm, Mark the filament 70mm above the head, and use the controls and tell it to extrude 10mm at a time. Do this 3 times and then measure how far away your mark is. By the math, it should be 40mm away from the head. If you're more than 1mm either way, you're probably going to consistently see the issues your mentioning and no amount of need leveling is going to solve it. Technically a simple fix, but there is some math and code to send to the printer and someone here can easily help along the way.
Well the population itself is not even 1/100th 'at capacity' in the US. The distribution of the population is certainly a cause for concern, and infrastructure is sorely in need of upgrade, but those are management problems. These are arguably exacerbated by the the fear of 'who' the increased infrastructure would be for, but it is in no way driven by lack of resources or space. We have huge swathes of crop land subsidized into non-food crops, crazy amounts of unoccupied land, ready access to transportation if we had drivers. Maybe the most restrictive resource is water and workforce. No magic fix for the former, but immigration would directly fix the later.
You may not want more towns/cities, and additional building should be done with pollution in mind, but it really comes down to 'not in my backyard'-ism. There are a lot of people that exist, through no fault of their own, and to say they should live in even more cramped and dangerous environments than you just so you can afford more elbow room is exactly my point. It's not legal or logistics reasons the US doesn't want more immigration, it's primarily culture and racism. Good or bad, i'd be willing to bet when someone moves in down the street with a German accent most people will think, at worst, it's kind of interesting, but if they are dark skinned or speak Spanish, a whole bunch of people that didn't bat an eye at the German immigrant, legal or otherwise, will suddenly have concerns about 'over population'.