Encrypted document vs Key manager - security question (slightly off topic)

[Daniel Mang]

Hi

Maybe one of you knowledgeable people on this list might be willing to
give me your qualified opinion on the issue. Sorry if this post is too
far off topic.

Years ago, before I had really heard of key managers, I started
putting login credentials, PIN numbers and other private and
confidential information into a file that I would then encrypt with
GPG and keep on my computer. When I was on Linux I had the whole disk
encrypted, now that I am using a Mac I use File Vault to encrypt the
whole disk. I use the GPG Suite for Mac by GPG Tools. Of course I
would erase the unencrypted original of this file and only keep the
encrypted file, but I am a bit worried about the feasibility of really
erasing anything on an SSD (I'm on one of these 12" "Retina"
MacBooks). I work on two computers, and for this and other reasons, a
while back I put most of my documents in the cloud using an instance
of NextCloud on a server in France run by very security conscious
friends. I sync that encrypted file with my passwords etc along with
everything else. When I open my encrypted file to consult or modify
it, of course I first turn off sync and only turn it on again after
the plain file is trashed, so that only the encrypted file ends up in
cloud storage.

So my question is, do you think this system is ridiculously insecure
or is it at least no worse than using something like KeePassX?

Kind regards

Daniel Mang