If you haven't discovered it already I would suggest occasionally making a JEX backup of your notes and resources and storing it in a safe place (i.e. not on the computer where Joplin resides).
File > Export > JEX - Joplin Export File
This produces a single compressed file containing a plaintext copy of each of your notes and a "Resources" folder containing, funnily enough, all your resources / attachments. If you associate the JEX extension with a compression program, such as 7-Zip, you can even click the JEX file to open it and have a rummage through. The files all have Joplin's internal reference as their file name but I guess that is so that if you restore a backup into Joplin all the links between the notes and resources will still work!
Having a JEX backup handy has saved me several times when I have done something that, with hindsight, could at best be described as stupid...