Hatte die Signal Foundation sich nicht schon irgendwo mal geäußert, dass sie für die Schnittstelle zu WA gar nichts „entwickeln“ möchte!?

2 things I found on a quick search:

1st Look if your GPU is actually designed to have a „headless“ start - if not you most likely need that dummy adapter that others mentioned

2nd In the bios settings look for something like an “Halt on all errors” option and disable it. If the GPU is the problem than you might get to start it anyways without any monitor connected

Can you please clarify what you mean with

it doesn’t even post

Do you mean it is not reachable via its IP address or are you trying to ssh into it?

My first approach would be to check the bios settings when you’ve a monitor connected. Maybe there is some kind of strange setting set there!?

I second Valetudo. I’m using it on a roborock S5 and installation was pretty straight forward. Even if it takes more effort to „root“ your vacuum it is definitely worth it. I also integrate my vacuum in HA over mqtt.

For automated container updates I can highly recommend watchtower. It also works with updates for specific releases/versions where you’re not using the :latest tag. It was also relatively easy to configure for my small setup of 15 containers.

SelfToasted

Does the container offer SSL (https)? If so try clearing your browser history so that you can confirm again that you trust this website. Same goes for the extension (uninstall/install again). Most likely your ssl cert changed when you did the DSM Update.

But I would assume you’re used to using a ‘manual’ keyboard whereas if you only grew up on touchscreens its probably more difficult to get familiar to.

The prevelance of touchscreens much rather results in people lacking skills/efficiency/speed when using a regular computer keyboard

According point 2: I choose homepage over Heimdall. It has more direct integrations (e.g. Homeassistant, Synology, Paperless-ngx, Warchtower…) where you can display specific information directly on your dashboard. It is easily set up by a couple .yaml files. You can find lots of examples online and in the documentation.