Do you have a family member or a close friend who is tech savvy and is also using BW? If yes - you could set up an emergency access, so that they can initiate an account takeover should you somehow entirely lose access to everything and need it recovered. The original intent is to take control of an account of a deceased person.

If that's not an option - just save your master PW somewhere offline. Another person suggested paper, but honestly evaluate your own threat levels and consider having an offline backup of it on a device that never connects to the internet (e.g. a flash drive that you only connect with the internet turned off). You can also make an offline export of your vault onto that USB in case you get locked out and need at least your data recovered. Generally don't overthink your master PW, a 10 word passphrase with a number is good enough, if it's not a grammatical sentence - even better, it can even be not in English. There are also ways you can "salt" your PW in addition, say, your PW is hello-friend-joke-inventing5, you can save it as housing2-hello-friend-joke-inventing500 and just remember to remove the extras. If you are not specifically targeted and don't click on fishing links, then honestly even if you save your master PW in your own BW vault nothing will happen, even less so if it's salted.

The only way to truly mess up your vault is to change keys without logging out your devices, but BW explicitly warns you at each step of that process, so it's up to you not to ignore the warnings.