I remember seeing warnings about, "Don't update your Wii/WiiU/Switch firmware AT ALL! STAY ON FACTORY IF YOU EVER WANT TO PLAY BACKUPS!"
End results.... it made no difference. All of those systems were 100% hacked and the firmware version made absolutely no difference. Most hacks were software based but a few were hardware. Sure, it didn't happen overnight but it did happen.
The Switch 2 will either be completely hacked one day (no matter the firmware version) or go the route of the Xbox/PlayStation and wide scale hacking will never happen on it.
TLDR; Enjoy your Switch 2 and update to whatever the latest firmware is and party on. A hack may, or may not, come and if it does, your firmware version won't matter.