AWS offers exactly this. You upload to S3, then reserve the storage (at a discount) for a few years. You can pay upfront.
It's not cheap, but it's the most reliable and secure option for a business.
We are digital librarians. Among us are represented the various reasons to keep data -- legal requirements, competitive requirements, uncertainty of permanence of cloud services, distaste for transmitting your data externally (e.g. government or corporate espionage), cultural and familial archivists, internet collapse preppers, and people who do it themselves so they're sure it's done right. Everyone has their reasons for curating the data they have decided to keep (either forever or For A Damn Long Time (tm) ). Along the way we have sought out like-minded individuals to exchange strategies, war stories, and cautionary tales of failures.
AWS offers exactly this. You upload to S3, then reserve the storage (at a discount) for a few years. You can pay upfront.
It's not cheap, but it's the most reliable and secure option for a business.
Use pcloud business account to store the data. Or just buy a 10tb lifetime account for $1,000. The account will be a company assistant that can be used for life.
You could try out Storj. It's a globally distributed cloud storage. You can pre-pay and get a 10% discount by adding Storj crypto to your account. 10TB would be roughly $40/mo before any discounts.