Hello,
There were a couple of discussion about that wifi in the old forum
https://archived.forum.manjaro.org/t/intel-iwlwifi-driver-not-working-on-kernel-5-4/115341/2
https://archived.forum.manjaro.org/t/latest-update-5-3-to-5-4-no-wifi-intel-r-wireless-ac-9462/115575/24
Of course you can’t switch back to 5.3 kernel, but maybe you can test a different kernel, maybe worth even 4.19 kernel.
Disable mac address randomization and IPv6 too