This might also become a hassle since basically all residential connections (likely of OPs friends) have dynamic IPs - if someone wants to join while OP is away, but their IP has changed since their last connection, now they have to wait on OP to update the firewall rules.
Apart from getting your MSA token stolen, there’s not really much that can get around server login (yet). All online-mode logins pass through Microsoft (part of the reason why Xbox service outages seem to affect Minecraft so much).
If your friends all individually seem to stay within some certain IP ranges (ex, first handful digits always stay the same, 12.34.56.xx), then I’d say go ahead with whitelisting them fully (ex, 12.34.56.xx --> 12.34.56.0/24, CIDR notation). If they jump around unpredictability, I would stick with the username-based whitelisting and online-mode-only.
yes, it’s mostly things like games or software
though, I have seen more & more reports of people finding malicious disguised LNK files in their downloads and torrents, which will run some arbitrary command if you open that: Windows does not ever show the LNK extension, so a file could be named “<whatever>.mkv.lnk”, and you would only know if you checked the “file type” column in Explorer (which would read “Shortcut” instead of something like “Matryoshka file”), or when you see the cmd.exe window flicker open and close.
bonus edit: LNK is the native file extension that Windows uses to link app shortcuts, such as the shortcuts on your desktop.