I was looking for backup option number three. Lightroom Classic with the 1tb cloud storage option looked like for a little extra I could upgrade LR too.
First of all nothing that you are doing now is a True backup. It is simply a file copy. Carbonite has individual plans that will backup all of your critical user data (including LR Catalog and all of your image files). With your existing file copy. you are simply copying and propagating errors to the copies. If you have a file on your disk and it gets corrupted, then the corrupted file gets copied to the other location with your present scheme. If you have a Word document and 6 months later you discover that you made changes and want to recover the original document from 6 months, 6 weeks or 6 days ago, you can do that with your present set up. With a true backup app, you can find that version of the same file on. your system as it was saved 6 months, 6 weeks, 6 days ago or 6 hours ago. Carbonite will do that for you. If you want to use a backup to an external disk, then there are Windows based apps like Apple's TimeMachine that will provide you with the same backup protection as a cloud base service like Carbonite. One that I would recommend is Acronis. I use it to supplement the TimeMachine Backup on my Mac.
Backup apps run in the background constantly and automatically So your backup disk is never more than 30 mins behind the master files. You should plans on total disk failure at some point and have a recovery plan in place for when you primary disk drive fails. The app that I have mentioned will do that. For that extra $10USD/month you can subscribe to a Carbonite backup that will backup not only noir primary disk but an External disk too,
The only drawback for a cloud based backup is the recovery from the cloud can take days or weeks in the cased of a total disk failure.