Try to install additional drivers:

Open terminal and do

List the network devices find the name of the WiFi interface.

sudo nmcli device

returns:

DEVICE           TYPE      STATE      CONNECTION 
wlp58s0          wifi      connected  ShareWiz         
lo               loopback  unmanaged  --   

Then do this command with your interface name.

nmcli -p -f general,wifi-properties device show wlp58s0

This should give you lots of info about it including what driver you are currently using.

===============================================================================
                           Device details (wlp58s0)
===============================================================================
GENERAL.DEVICE:                         wlp58s0
GENERAL.TYPE:                           wifi
GENERAL.NM-TYPE:                        NMDeviceWifi
GENERAL.VENDOR:                         Qualcomm Atheros
GENERAL.PRODUCT:                        QCA6174 802.11ac Wireless Network Adapter
GENERAL.DRIVER:                         ath10k_pci
GENERAL.DRIVER-VERSION:                 4.15.0-66201911071317-generic
GENERAL.FIRMWARE-VERSION:               WLAN.RM.4.4.1-00079-QCARMSWPZ-1
GENERAL.HWADDR:                         9C:B6:D0:D3:FD:CD
GENERAL.MTU:                            1500
GENERAL.STATE:                          100 (connected)
GENERAL.REASON:                         0 (No reason given)
GENERAL.UDI:                            /sys/devices/pci0000:00/0000:00:1c.4/0000:3a:00.0/net/wlp58s0
GENERAL.IP-IFACE:                       wlp58s0
GENERAL.IS-SOFTWARE:                    no
GENERAL.NM-MANAGED:                     yes
GENERAL.AUTOCONNECT:                    yes
GENERAL.FIRMWARE-MISSING:               no
GENERAL.NM-PLUGIN-MISSING:              no
GENERAL.PHYS-PORT-ID:                   --
GENERAL.CONNECTION:                     ShareWiz
GENERAL.CON-UUID:                       dbade843-cae4-4d9a-9403-3ca0f4ad72cd
GENERAL.CON-PATH:                       /org/freedesktop/NetworkManager/ActiveConnection/9
GENERAL.METERED:                        no (guessed)
-------------------------------------------------------------------------------
WIFI-PROPERTIES.WEP:                    yes
WIFI-PROPERTIES.WPA:                    yes
WIFI-PROPERTIES.WPA2:                   yes
WIFI-PROPERTIES.TKIP:                   yes
WIFI-PROPERTIES.CCMP:                   yes
WIFI-PROPERTIES.AP:                     yes
WIFI-PROPERTIES.ADHOC:                  yes
WIFI-PROPERTIES.2GHZ:                   yes
WIFI-PROPERTIES.5GHZ:                   yes
-------------------------------------------------------------------------------

If you want to switch to another driver then get it from here its in a.deb

https://launchpad.net/ubuntu/+source/backport-iwlwifi-dkms

Remove the driver that is currently being used:

sudo rmmod [drivername]

Then

sudo modprobe backport-iwlwifi-dkms

Not sure if its that or just

sudo modprobe iwlwifi