[SkywalkerPD]

Instead I use a 5G dongle. This worked until about a week or so ago, but after that I started getting problems

Does it resume working if you go back to an older build (from about a week or so ago), or is this environmental (no longer works even with an older build, maybe a new noisy neighbour, router needs a reboot etc.)? If it resumes working with an older build, which is the last working build? Are there any errors in dmesg relating to your 5G dongle with latest builds?

Will check and come back to you...