USB Audio with kubuntu 26.04 results in audio glitches

Question 1

i currently have highly annoying audio glitches when listening to music: apps tried:

Quodlibet
VLC
bashgst-launch-1.0 playbin uri=file:///home/stefan/…/Schiller__Atemlos/1__02__Schiller__Tiefblau.flac
ffplay 1__02__Schiller__Tiefblau.flac

that all with my USB Audio Interface (iBasso DC06).

(build in laptop speakers seem to work)

for me it sounds as if the USB bus is overloaded with data / the priority for the data is to low..

Operating System: Kubuntu 26.04 LTS
KDE Plasma Version: 6.6.4
KDE Frameworks Version: 6.24.0
Qt Version: 6.10.2
Kernel Version: 7.0.0-22-generic (64-bit)
Graphics Platform: Wayland
Processors: 16 × Intel® Core™ i9-9980HK CPU @ 2.40GHz
Memory: 32 GiB of RAM (31,1 GiB usable)
Graphics Processor 1: Intel® UHD Graphics 630
Graphics Processor 2: NVIDIA GeForce RTX 2060
Manufacturer: ASUSTeK COMPUTER INC.
Product Name: ZenBook Pro Duo UX581GV_UX581GV
System Version: 1.0

this problem only showed up recently. any idea how to narrow down / analyze the problem?

Question 2

maybe something in my system changed with out me noting..

at least i can not reproduce the behavior.

before this i had an additionally founding: this happens only if i use the USB Audio Interface directly on the laptop - if i have my USB3.0-HUB (with build-in Network-Connector) in between, the problem was completely gone.