Every cloud provider has compliance locks which even root user cannot disable, version history and you can setup your own copy workflow storage container to second container without delete/update access to second one to two different people or whatever.

You don't need to do any of it offsite.

Having had to restore databases from tapes and removable drives for a compliance/legal incident, we had a failure rate of >50% on the tapes and about 33% for the removable drives.

I came away not trusting any backup that wasn’t on line.

At $50/month scale a lot of things are possible. Most companies cannot store their data in a hard disk in a safe. If you can, then cloud is a convenience not a necessity for you. I.e. you are perfectly fine running your storage stack for the most part.

My company is not very big(100ish employees) and we pay $200k+ for AWS in just storage and AWS is not even out primary cloud. If we have to do what you have, it is probably in bandwidth costs alone another $500k. Add running costs in another cloud and recurring bandwidth for transfers , retrieval from Glacier for older data on top of that.[1]

Over 3 years that would be easily $1-$1.5 million in net new expenses for us scale.

No sane business is going to sign off on +3x storage costs on a risk that cannot be easily modeled[2] and costs that cannot be priced into the product, just so one sysadmin can sleep better at night.

[1]your hard disk in a safe third component is not sensible discussion point at reasonable scale.

[2] this would be probability of data loss with AWS * business cost of losing that data > cost of secondary system.

Or probability of data availablity event(like now) * business cost of that > cost of an active secondary system .

For almost no business in the world the either equation would be valid.

For example even the cost is 100B dollars in revenue with 6 nines of durability the expected loss would be only $10,000 (100B * 0.000001) a secondary system is much costlier than that.