RE: What Kind of Maintenance Do I Need on Linux?

For older laptops, even if you find different recommendations online, they're not all true, I tested a few of them but didn't find a better one than "antiX".

NetworkManager-wait-online.service is not a problem, it'll just wait until you have an active net connection before continuing booting. You could disable that but only if you are bothered about those 5 secs while booting.
About the Bluetooth, I think you have the bluetooth.service off or not present, that blueman-mechanism.service is another app service to manage the bluetooth, you can try "sudo systemctl disable blueman-mechanism.service", otherwise you can look for other ways how it can be disabled. About the docker.service, you probably told it not to run your docker images at startup, but the service still starts, it just wouldn't load your docker images.
You could disable it and enable it every time, but I guess better leave this alone if you plan to use it often.

I don't run and video encoder, I wanted to but it won't work on my rented vps and the laptop I have for a spare is too low specs for encoding. I'm only running nodes for the SPK network and Ragnarok.