Hi,
It is sad to hear that you lost your notes. I am just guessing that your FF profile went wrong partly after reset. It should be very rare case. I have never got any bug report about it before and I have had many reset on my computer without problems since 2017. But yes, please save your notes regularly. It is the solution for it.
Syncing to cloud/somewhere is on the feature task queue and maybe it will come in 2021/Q2.