Bluetooth can be managed with systemctl and bluetoothctl.

https://www.makeuseof.com/manage-bluetooth-linux-with-bluetoothctl/

In my experience I find just running bluetoothctl to enter the interactive mode easiest. You can enter commands without prepending bluetoothctl. You can use help at any stage. So you want to use systemctl to make sure Bluetooth is running, then enter bluetoothctl. Make sure the device is discoverable and pairing is set to on. Start your [headphones/whatever] in pairing mode and run devices. When you see the device run pair <numbers/address>. Only use the numbers. You may have to go into settings and select the device in the sound applet.

My situation doesn't require a logout timer, but if I'm walking away from the PC I just use the shortcut Super + ESC. Alternatively, there's many ways you can create a basic Bash script that when invoked times down to a systemctl suspend command. Or possibly the hybrid-sleep option could do what you want. See systemctl -h for possibilities.

Blanking the login screen is something that will be implemented shortly. Maybe I'll work on a script for that because it annoys me too. Fortunately I rarely use it. I'll repost if I do this.

I really don't think the two years people are saying in this thread is realistic. The hard work and core is written. What is there is stable. I think they will get this completed much sooner. They do have a hardware business to support after all.