Encripted cloud service

I would suggest an alternative that allows you to use any of the "Big Ones" like iCloud/OneDrive/GoogleCloud/ Dropbox.

Buy Cryptomator on whatever device(s) need access and set up a single vault on any cloud service you use. This vault will be client-side end to end encrypted which means its just you with knowledge of and managing the encryption keys. Put them in your password manager for a while until you memorize.

Remember, if they aren't YOUR keys, it doesn't really belong exclusively to you.

Tresorit is the best of them all.

It has all the features that matter, it's fast, it's E2EE, have automatic photo upload, it's cross-platform ... ticks all the boxes.

It also ticks the high price box, though.

Besides that you have Filen (good but not great, very cheap for a cloud storage with E2EE), Skiff Drive (lacks some features, but it will be my preferred cloud storage as soon as they have automatic photo upload), Proton Drive (lacks a lot of features and it's expensive), MEGA (I have a legacy account, it's 50GB that I use for the non-sensitive data), ...

Filen serious issue https://github.com/FilenCloudDienste/filen-desktop/issues/182

I've heard good things about backblaze which has an s3 compatible API (meaning it supports most tools). Like s3 this probably means it has a similar learning curve

Mega is another one but I do remember hearing about it being acquired by a suspect Chinese entity, as well as other latent issues I dont recall. But if I remember correctly files are encrypted on the client-side. Can anyone recommend or provide a ink to some of the issues raised?

If I had to make a decision at the drop of the hat, I'd go Proton's way.

Btw iCloud is also e2e encrypted and if you set advanced data protection then only you will have the key. Even Apple is unable to access it

just use rclone, then everything's encrypted