I have to admit that I haven't carefully read all 43 posts that are here, but has there been any Bluetooth trouble mentioned so far? Here's why I ask ...
Today I received my new Arteck multi-device mouse from Amazon. It's a near duplicate of the Logitech Triathlon mouse that I've used for years, except that it has multiple DPI settings, it's rechargeable via USB-C, and costs about 1/3 what I paid for the Triathlon.
My problem is, I can't make it connect with my Plasma laptop (on which I've used the Triathlon mouse for years) as Device 1. It pairs and is trusted, but cannot connect. It connects and works fine as Device 2 with my Windows 10 media machine that controls my TV, and likewise as Device 3 setting with my Samsung smartphone. It just won't connect with my Solus laptop.
After trying to make that work for a while, I decided to give up for now and just go back to the Triathlon mouse until I can figure this issue out. It took me 4 tries to get that mouse - the one I've used for years - connected. Of course, I had the laptop "forget" the mouse in between attempts. And I rebooted once. The fourth try was successful.
The laptop is a DELL Latitude, all Intel inside, and has never given me a problem like this before. Any ideas?