Bluetooth issues - XPS 13 9370 - Logitech mouse and keyboard

I bought a Logitech K380 Bluetooth keyboard and later bought a Logitech M337 Bluetooth mouse so I wouldn't need a dongle. It worked really nicely for a month or two, then stopped working.

Bluetooth Devices in Windows 10 says they're "Paired" but won't connect. Strangely, all other Bluetooth devices work fine with my laptop (my speakers, headphones, etc). Just the keyboard and mouse are having issues,

So far I have:

• Tried removing the device (select device, click Remove), but they keep showing back up.
• Tried deleting from "Device Manager". They still show back up when I restart.
• Uninstalled the Killer Bluetooth/wireless driver, restarted and let Windows choose a driver.
• Uninstalled the driver, restarted, installed latest Killer driver.
• Turned off Bluetooth in BIOS, restarted, turned back on in BIOS.
• All windows updates and driver updates.
• Gone into device manager / Bluetooth adapter properties and made sure to un-check the box to "allow this device to turn off to save power"

The keyboard and mouse still won't connect.

However, I have gotten it to work for a while (anywhere from an hour to a couple of days) by doing either of the following:

• System restore back to a point before it stopped working.
• Format and re-install Windows 10

Obviously I don't want to have to keep formatting or restoring the system every day. And it's odd that my other Bluetooth devices don't have issues connecting and reconnecting.

Can anyone help?