Many issues with Ubuntu 20.04 on 9310

Hi Everyone.

I'm having quite a few annoying issues with my Dell XPS 13, 9310 with user installed Ubuntu 20.04.

Running Kernel: 5.10.0-1051-oem, xserver-xorg-video-intel 2:2.99.917+git20200226-1, BIOS is up to date.

* USB-C to displayport/HDMI on a 4K screen causes odd flickering and then every now and again the screen goes blank for a few seconds. Works fine using a Thunderbolt to HDMI and the external screen works fine with other machines. Tried the `i915.enable_psr=0` setting with no change.

* WiFi adapter fails every few times when coming out of sleep. Requires a reboot to get it working again:

ath11k_pci 0000:72:00.0: qmi failed to respond fw mem req:-110
ath11k_pci 0000:72:00.0: qmi failed memory request, err = -110

* Bluetooth adapter isn't found on first reboot, Ubuntu seems unable to connect to the Bluetooth adapter at all as if it hasn't even been powered up. Shutting down and waiting a few seconds then booting up again seems to resolve temporarily but is incredibility annoying

* High battery drain when sleeping, the battery drains over 10% in less than 12 hours sleeping. My previous Lenovo with Ubuntu 20.04 would drain about <1% in the same time.

Any help resolving these issues would be greatly appreciated.