Does this support other targets like twitch VODs?

Mattermost does not have E2EE to my knowledge.

Not E2EE though, or at least not fully.

XMPP only does it with certain client extensions. And Matrix only does it when the rooms are set up this way. SimpleX does what you want, but is kind of unintuitive for the average user.
I say go with Signal, it does what you want and is idiot-proof.

Consumer CPUs were lacking ECC reporting, so you never really knew if ECC was correcting errors or not.

Have you considered TrueNAS Scale?

In case your Lenny client concatenates the dot to the link like mine: https://medium.com/@joshuaavalon/encode-video-with-handbrake-on-server-17b6127f6ac7

How much effort have you actually put into trouble shooting the issue? Maybe it is just a wrongly set CPU governor (performance, instead of ondemand or something else)? Or a certain kernel flag that have to be set on boot?

I just wish NewPipe would open piped.video links automatically.

Hm, you could set up a virtual machine on whatever host OS and have Unraid run in that instead.

Honestly, when Unraid is the culprit, why not change that instead?

Does a PiKVM to enter the password manually count?

Modern Android versions can use DoH (DNS over HTTPS) which can not be intercepted. If you don’t have this option or are not sure how to configure it, you could use the Quad9 app to enable secure DNS. This way you can make sure it is not related to DNS. Frankly, I can’t imagine they are blocking the IPs of the DuckDNS servers directly.

If it’s just a DNS block, you could use a different DNS server. You should do this anyway in my opinion.

I’ve heard good things about https://www.tarsnap.com/ and https://www.rsync.net/

Oh wow, apparently I didn’t see the “DSL” in the model name. You could try to figure out whether it is physical identical to another model that doesn’t have a modem built-in (except for the modem obviously) and use an image for that, if you don’t need the modem functionality.

Oh, you’re right. In this case: https://freshtomato.org/

https://www.asuswrt-merlin.net/ as a first step.

Do you miss anything?

It’s still called that way: Dynamic range compression