Best thing to do is to keep sensitive data away from any cloud service. I just keep things I can afford to lose or it's not private so I don't have to worry about switching to other privacy focused services.
The cloud is more about mitigating data loss. I don't think most of you know what it takes to really setup a system at home to mitigate from the potential loss of user data. Such as family photo's, etc. You know information that can not easily be replaced.
I have plenty of customers, my office included, that requires financial records to be kept for so many years. This is built right into MS's 365 platform. Even deleted data is held onto for years. This requirement really limits the use of many 3rd party options.
The cost of even a basic proper local data store with redundancy scales up in cost quick. Looking at needing Raid 1 at bare minimum, be software or hardware, just to allow for loss of a single drive while allowing for continued uptime. Along with that you'd need a secondary storage setup offsite. That is kept synced at all times. And even then you are not completely safe. On top of the backbone of the operation you'd want some type of file versioning, either via snapshots or other means. On top of that you'd want to protect your files from long term data rot, which means you'd need a file system built to mitigate datarot from the start. Such as ZFS.
You can have everything I have listed above, and still loose your files....
Keeping your data private even on a cloud service is more of a software issue. There are plenty of tools out there that will take advantage of such cloud platforms and keep your data secure. If you don't want MS holding your encryption key, encrypt it yourself. Same goes for any service.
I love Onedrive/Sharepoint. It is by far the cheapest cloud storage solution and one of the most redundant and dependable, but scaling storage past 1TB gets expensive quick for any option. Not just MS. But I'm all for taking advantage of a service from a dollar standpoint.
If you like wasting money, go ahead. But I'd recommend you stick to what ever makes sense on a dollar per GB scale, as well as convenience.
Too many Brand loyalist on this site. It's crazy how quick people pick up a pitch fork against one brand, yet sign praise another. Just like any product ever made, you should never focus on brand. Focus on the product! Plenty of people on here would rather loose their first born child than be forced to use a non intel gaming computer.
When it comes to important memories such as pictures of your family, I hope most of you are not keeping them on some old HDD waiting to die....