I would look into software that was designed in general for collectors, be it stamps, non crypto coins, things like that.
At a guess most of them could be adapted to work with crypto, or at least give you something that should be better then excel.
The downside, is going to be that you are now exposing what you have. So if someone does not know the true value of your crypto collectable collection. If they see what you have in the app, they will know....
-Dave
Interesting point, I'm trying a few software as we speak. most of them give you the ability to create all kinds of customer fields which can help a lot.
I understand what you mean about the phone app and privacy, note that all the SaaS software is not as secure as it's should, so exposure will be not a great idea.
if to use the software it's better to make sure it's a brand, common cloud provider, MFA & 2Fa, encryption will be a nice addon.
QB