First, it's always good to remember general security best practices: update your devices, don't reuse your passwords, make sure you have backups of important data, don't visit shady websites, and so on.
In regards to the discovered Wi-Fi vulnerabilities, you can mitigate attacks that exfiltrate sensitive data by double-checking that websites you are visiting
use HTTPS. Even better, you can install the
HTTPS Everywhere plugin. This plugin forces the usage of HTTPS on websites that are known to support it.
To mitigate attacks where your router's NAT/firewall is bypassed and devices are directly attacked, you must assure that all your devices are updated. Unfortunately, not all products regularly receive updates, in particular smart or internet-of-things devices, in which case it is difficult (if not impossible) to properly secure them.
More technically, the impact of attacks can also be reduced by manually configuring your DNS server so that it cannot be poisoned. Specific to your Wi-Fi configuration, you can mitigate attacks (but not fully prevent them) by disabling fragmentation, disabling pairwise rekeys, and disabling dynamic fragmentation in Wi-Fi 6 (802.11ax) devices.