PETG print quality from good to bad, overnight

[lancerobrts]

Might be 'Spaghetti infill' set in Cura experimental mode.

Not sure how to check that, but I've tried so many other things to try fix it, but so far nothing has worked.The print starts nicely, but then by the second layer the spaghetti starts to come out and when it gets to the infill everything starts to look like a huge mess....I've tried changing print speeds, temperatures, infill type, position of the print on the bed, quality of the print, wall thickness, etc. etc. etc.I even changed the filament tubing, just in case there was a blockage in it and the plastic wasn't moving through easily enough. My next thought is that the thermistor is not picking up the correct temp, and it's not adjusting correctly. Or maybe the heat block isn't keeping the heat up... I'm quickly running out of ideas.

[Bikeracer2020]

It's the bottom menu choice labeled Experimental, pic shows the part of that menu.