Really shouldn't be hard to figure out given the events of the past few days...

There's a plugin for Jellyfin that will analyze the audio of your content to automatically tag intros, recaps, and credits

If you're feeling adventurous, you could cut your front panel audio wires and connect them to a new 3.5mm jack inside the case. It might be a lil janky but it would get the job done for <$10

AudioQuest Dragonfly wouldn't be a bad way to go. I have a Red on my PC because the onboard mobo audio picks up USB noise. I've also got a Cobalt for my phone/headphones. They have a firmware update utility for the Red/Black that you manually install and can uninstall afterwards, the Cobalt ships with current FW and hasn't been updated yet. That said, they're pretty expensive for what they are and I got both of mine 50+% off. If you're considering a "proper" audio setup, I'd go straight to to the Denon unit you're looking at

You're thinking of adenine when it comes to DNA/RNA

Listen to this guy. Most LED tape is 12V or 24V. A 5V 20A power supply may meet your wattage requirement, but the LED tape will need it at 12V to function properly.

If you have a local audio/video company, give them a call. Most of the big brands have a whole product line geared towards hospitality use that gives much greater control over "smart" features. They're usually not available to the general public, but an A/V dealer should be able to hook you up

If it's cable internet and not fiber/DSL, I'd look at connecting the ISP's coax to the house's coax. Provided all of the house's coax ports are connected to a splitter, you could feed the ISP coax into the nearest port and plug the cable modem into the office port.

My mother is a fish

I was originally going to host my instance on my own hardware but decided to use a $6/mo droplet on DigitalOcean. Seems to work well enough for me and my LCS bot. Picked up a domain off Google Domains for $20/year or so. It's been a fun project and I've learned a lot along the way.