Das hört sich an als könnten wir auf Deutsch schreiben 
But let’s continue in English in case others have similar issues.
You can just copy-paste from, for example, the explorer straight into the text. If not, you may need to enter a few more forum topics (10 total) and scroll through some individual posts (30 total). It is part of the Discourse spam/bot protection.
Printing that cube should not pose any particular challenges. That is a good sign as it means we can go through the basics and common issues step by step.
The changes from defaults that I spotted should not have caused any particular challenges. So if you encountered air printing already at the second layer, something fundamental seems to be wrong.
Things we (think we) know:
- The bed is straight and level
- With the first layer printing, we probably do not have any AMS and Filament path issues
Things to check:
- Build plate adhesion: Did the first layer detach anywhere? Did the air print have a blob at the nozzle?
- Nozzle damage: Since you mentioned repeated nozzle problems, is your current nozzle bent? Even slightly? Taking a picture from the front and one from the side can help with that.
- Heat creep: Do you print with the top open? What was your chamber temp? Above 39°C, heat creep is very likely to occur. For larger, flat surfaces, ironing or for prints or when using moist filament, it can happen with as low as 35°C.
- (Partial) Nozzle clog: When you extrude filament manually into the poop chute, does it work? Does it flow straight or does it curl? If it curls, you need to perform cold pulls on it. Preferably the hot hex key method as the “simple” cold pull has a good chance of leaving residue in the nozzle. Do 2-3 in a row.
- Extruder clog: Especially after major issues, different types of extruder clog can occur. When doing the cold pulls, it is a good opportunity to check the extruder gears for abraded filament and clean it. In a worst case, abrasion can be seen on the filament.
A few further basics:
- Especially new filament is moist. Those bags are not moisture proof, they are only moisture retardant. But they have spent weeks on the seven seas… So the only safe assumption is that new filament is moist. And that can have rather drastic consequences on thermal and rheological properties which high speed printing is much more sensitive to than prior generations. So best dry new rolls of filament before using or storing them with plenty of dessiccant.
- Build plate adhesion on the Textured Plate can be lost very rapidly and surprisingly. It is a sign of the “valleys” of the Textured Plate clogging up with dust, etc. That dust, etc. needs to be properly scrubbed and washed out with plenty of water, dishwashing liquid and a stiff, clean brush every once in a while. If that first layer (partially) looses adhesion, it’ll be picked up and dragged around by the nozzle. Worse, high speed collisions can transfer sideways loads on the nozzle.
There’s more of course, but we do need to narrow down the field of possibilities.
& 
Addendum:
Many thanks for those pic’s. On one hand, it looks much better than your description led me to believe.
I’d start with the basics. Not build plate adhesion, that looks good, but, well, yes. Dry that roll of filament. That’ll make getting a good print much easier. Remember, new rolls are frequently moist.
While it is doing that, you may want to close up the rear panel again to avoid warp inducing drafts.
When you are ready to try again, probably also use some glue stick on the Smooth PEI, take a 1/8 to 1/4 of a paper towel, soak that towel and use it to first dissolve the glue stick lines and then distribute an even PVA/Water film across the plate. Dump the paper towel with the excess PVA after that (which is why you only want to use a small one ).
That should already take you a long way. If problems persist, I’d look at speeds and/or flow. That single high speed, high flow line at the bottom leads to weaker layer adhesion while those fast, high flow layers at the top promote curling, generating sideways forces on the print from nozzle collisions which can rip off the print. Especially if there’s moisture in the filament.
I was initially concerned that layer time may be an issue, but there’s nothing in the preview that I consider a smoking gun.
A further note, the print must have remained (reasonably) attached after layer 2 and only fractured right at the end. Otherwise, you would have printed a birds nest (literally) rather than a locally pretty good, but torn off, cube.
While there’s clearly something seriously wrong with the high speed, high flow layer number 2 (where also the fan kicks in, but playing with that is opening Pandora’s box and usually not neccessary with PLA), there’s some warping already visible on layer 1. Another sign that the filament is properly soaked.
&
