The thing with online backups is that you have no guarantee that your data will be available ( ever ) when you need to do a restore. Secondly, a restore will take ages ( depending on the size of the restore ) and lastly you have no control over your backup data .... you just give it away to someone you don't know.
A cloud is using the internet to store my personal data on someone else's computer in an unknown country.
I believe that sums it up.
Now back to the original post .... if the OP wants to keep 2 copies of a backup, that to me indicates that this data is valuable ( why else would you do that ) and the only good way forward is to store that in a correct environment which is safe and which you have control over.
Lastly, protecting your valuable data comes at a cost. The only thing that is free in this world is the sun rising in the east every day
( Then again you never know with the Japanese, they might want to turn that off one day.
)
Cheers ... McBie