Gaps in the print, maybe z-hop or extraction?

I changed to the e3d nozzel and tried PETG.
There the problems began…
After fixing a clog in the extruder i got error messages, Fan stopped, some more errors.
Maybe i made a mistake somewhere while assembling (although i had done that a few times without error). OK i repaced hotend, sensors, toolhead front housing, reset, and recalibrate (printer and flow)

Printing was working now, but had severe issues.
I tried to reduce speeds and retraction but sitll have gaps.
Maybe where the level-hop occurs ?
Have a look at the pictures below, all are PLA
Additionally the print stops a few times, display shows “ready” then, but after 30 secs it resumes. Is that a reboot ?

Any help, hints, remarks appreciated!