Wifi always disconnects when downloading anything and sometimes when loading pages

Hi @XXYYXX ,
Maybe you can try to enable manually with this terminal command:
nmcli networking on

sudo modprobe iwlwifi

and check if you have this module blacklisted in /etc/modprobe.d/ or /usr/lib/modprobe.d/.

I found these solutions in the following post:
Manjaro Not Recognizing Intel Wi-Fi 6 AX201 - #7 by bugger2

Please, post the output from the terminal:

sudo dmesg | grep iwlwifi

sudo rfkill list

Regards,