Just for clarity. You are doing lots of tests in /etc/nginx/sites-available.
Have you enabled the sites? i.e created links (http and https) in /etc/nginx/sites-enabled to the active website in site-available.

NB. Ralph will know this all better than me as he has nginx and I have apache2, but I assume this part works much the same. The simplest way to set these things up is to just follow a good step-by-step guide.

I can now see an A record for unboundtest.com (165.227.59.74, which is on Digital Ocean).
I can't see one for realupnow.com.

Have you got a static IP or just a dynamic one assigned by your ISP? Dynamic IPs periodically change.
By default most ISPs only provide dynamic IPs for domestic users. Business users, who also pay more, usually get a static IP.
And of course you can also run a web and/or mail server in the cloud (such as Digital Ocean).
To run a website accessible on the internet you really need a static IP.

You can check that your ngingx website is running OK by opening it in your browser on its internal (NAT, IP4) network address e.g. http://192.168.50.4 .
I assume there is already a correctly configured index.html in ngingx : on my apache installation there is one there by default that says "Apache2 Debian Default Page: It works!".
I also assume you have opened any firewall on your server for ports 80 and 443.
For now you may need to disable or bypass any automatic redirection from http to https as https won't work until you have a certificate.
My recollection of how my apache server works is that I have automatic redirection set up except for a bypass for letsencrypts certbot, as that obviously needs to see a http site when doing a challenge.

You can then check that it works using its web IP e.g. http://66.172.90.106 (if that's your assigned IP for realudown.com). This doesn't require a DNS lookup.
At this stage you will need to have opened your router firewall for ports 80 and 443 for this to work. On my router I have 'virtual servers' enabled to direct any incoming traffic on posts 80 or 443 to tunnel through to my webserver.

And then you can check that the DNS lookup works OK http://realupnow.com ....

FWIW I use Cinnamon (=gnome lite).

By default Cinnamon uses the applet sound@cinnamon.org.
You'd install it into the panel by right clicking on the panel and choosing Applets then your choice of applet.
By default Cinnamon also uses pulseaudio as middleware on top of alsa.
I'm unclear if the sound applet depends on pulseaudio being installed - as it's not something I've tried to change.

Agree, the CPU on my 5600G worked fine with 5.10, the issues I had were in support for the integrated GPU. This was improved with new GPU commits from AMD in 5:15.
I also have a nct6687-isa-0a20 fans sensor on the MSI AMD B550 MPG Gaming Plus Motherboard that I needed the 5.15 kernel headers so I could compile in its kernel module.
On my system upgrading to kernels 5.18 and 5.19 caused graphical glitching with Signal Desktop and Zoom and issues with getting reliable hibernation.

This strikes me as odd.

Anacron is useful on personal PCs that  you turn on and off so that scheduled cron jobs run just after startup (you can set a possibly randomised delay). This avoids  cron jobs not being run because your machine would be turned off at the time set for the cron job. On an alway-on server you would typically run such jobs in the small hours.

The jobs run by anacron are those in /etc/cron.hourly/, /etc/cron.daily/, /etc/cron.weekly/ and /etc/cron.monthly. If a job is unnecessary for you then remove it from the respective /etc/cron.*. If you think it's using too much resource consider doing it less frequently.

As I mostly hibernate rather than shut down my personal PC overnight I've also set it up so that it also checks if anacron needs to run any daily, weekly or monthly when its woken.

I can't think of any reason why anacron should delay shutdown.

Having checked your AX210 is a wi-fi 6E card, while my AX200 is only wi-fi 6.

The AX210 is only supported by linux kernels >= 5.10, i.e. the standard Chimaera kernel.

https://wireless.wiki.kernel.org/en/use … rs/iwlwifi

Nevertheless, even though you say its Beowulf based Linux refracta 5.10.0-0.deb10.16-amd64 is presumably a 5:10 kernel.

Well I've no reason to believe that appimage would solve the issue.
And I wouldn't want to start using appimage just to solve this issue given all the issues that all such similar solutions (appimage, flatpack, etc.) bring.

Remember I'm on Chimaera. I only upgraded to backports in the first instance to handle my newish hardware (AMD Zen3 5600G, B550 motherboard) and some issues with suspend/hibernate. If 5.15 works why upgrade further to a newer kernel if that has a regression?

But I an happy to try and pinpoint what that regression is, so that when I do move to a stable Daedalus and no doubt even newer kernel it has been solved.

Just too check: can I assume that having plugged in the usb drive you then rebooted, having prioritised the usb drive over the hard disk(s) in the bios?

On my set up at least there does seem a problem with the most recent versions of Zoom.
Start-up is painfully slow, with long pauses while it repaints the screen and meanwhile doesn't respond to the keyboard.
I thought the problem was related to the most recent versions using chromium libraries to write to the screen (signal-desktop uses a similar set-up). I downgraded to an earlier version (5.11.0, downloaded in June) that uses Qt libraries. I thought initially the downgrade sorted the problem but it hasn't. And I'm also now seeing the same problem with signal-desktop.
Hibernating and reawakening (as well the previously mentioned rebooting) does, at least temporarily, restore normal service.
Both Zoom and Signal install in /opt with their own set of libraries. Signal is from the Debian/Devuan repositories.

Any suggestions for what could be causing the problem?

Just for clarification, is this a general problem with the latest upgrade of grub?

I've just been updating my legacy-bios Chimaera installation (using synaptic).
There are lots of upgrades available today, including one to grub-pc, from 2.04-20 to 2:06-3~deb11u1.
I've installed all the other upgrades.
Is this safe to install the grub upgrade or will it just give me a grub rescue> prompt and a headache?

try /var/log/boot ?