There are many fixes listed on the links @cscs posted. I'm pretty sure one of those fixes should help with your issue as almost every known fix for this adapter is given in those links. You should be testing every fix suggested on those links not just the marked solution.
sudo systemctl mask tlp
Reboot after running the command.
If it is of no benefit then repeat the command using "unmask" instead to re-enable tlp.
Test this command:
nmcli networking off; sudo systemctl stop NetworkManager; sudo ip link set wlp1s0 down; rmmod -vf ath10k_pci; rmmod -vf ath10k_core; sleep 5; sudo modprobe ath10k_core ath10k_pci; sudo ip link set wlp1s0 up; sudo systemctl start NetworkManager; nmcli networking on
Please post the input and outputs of all those commands.
Be sure the LAN cable and any USB wifi dongle is not connected while troubleshooting your internal Atheros Wifi.
Please answer all the following questions if you would like to get your issue resolved.
Have you tested your wifi on other networks or with different AP/Router?
Have you tested on the live environment with a different DE to see if the connection behaves differently. Record the linux-firmware version and the kernel from any boot disk that performs adequately.
Have you tested alternate kernels? Install and test multiple kernel versions and list all tested.
Have you tested alternate firmware? Test firmware from Kvalo's Github website.
Please list any and all fixes you have tested. Details, details, details.
If none of these suggestions correct your issue pease post: