Brief bit, then long bit:
Find a cloud provider with client side encryption and archival backups. Get some local software (does Windows still have builtin backup software?) to automate backups to your local external drive, and will remind you to perform those backups.
Much longer part:
Lots of good points already. Yes, the data should exist in three places.
The working copy on your laptop, and the backup on your external drive are two places. You should use a cloud system as the third, to get that third copy physically separated from the other two.
I can’t recommend a particular cloud provider, but find one with client side encryption. That means the data is encrypted before it leaves your computer, and is not decrypted until it returns to a computer you control. The downside is that you must manage the password to decrypt your data. If you lose it, your data is gone.
I do not consider things like OneDrive, Google Drive, and Dropbox as backups. (They can be part of a backup solution, but that requires additional software.) They are just replicates of your working data, which is not a backup. The vast majority of file restores I do for people are because they deleted a file they want, or want to recover the original after making changes. Delete a file from your laptop and it gets deleted from OneDrive. (Yes, there are trash cans and such, but trash cans are not archives.)
Having a quick way to restore your computer to a working condition is great, but is going to take additional effort. Is that an important feature to you? The drive in your computer dies. You get a new one, install it, boot the recovery tool and reload it, and your up and working very quickly. If that is an important feature, then look for it in backup software. Your local copy should be able to fully restore your computer.
If all you care about is protecting your documents, then don’t worry about that feature. It is going to add complexity and take up additional space.