When it comes to privacy and security, I think you should treat all cloud providers equally. Use a client with client-side encryption so that the only thing that touches the provider is encrypted data.

Rclone is an example of a good client that can do this, and can even mount your cloud storage as a filesystem with its encryption layer in between.

Backblaze B2 with rclone and client-side encryption

I like Backblaze mostly for their business practices. The Backblaze devs answer questions on forums sometimes (Reddit link btw). The costs are pretty good, but there are cheaper options. $6/TB plus some API transactions. I paid almost a dollar last month for a couple hundred GB of data and transactions.

Plus their drive failure publications are awesome.

This is worth mentioning :

• https://en.wikipedia.org/wiki/Tarsnap
• https://www.tarsnap.com

BitWarden provides some encrypted storage on their paid tiers. I think it's very small, like 1GB, but it's E2E.

Apple iCloud storage is actually E2E too if you turn on Advanced Data Protection. (Note that not all iCloud features are E2E, like email, for example.) And the price is pretty comparable too. Naturally this works a lot better if you're on a Mac, but just FYI.

Filen.io is really good, but lacking features in their apps. But they're about to release a new desktop client with webdav and rclone support.

The troposphere?

The cheapest one + rclone crypt and or cryptomator / veracrypt

I'm using BorgBase with Vorta (desktop client for Borg Backup) and I'm pretty happy with it.

Cloud is just someones computer so I wouldn't ever upload anything without encrypting it manually myself first just in case .

I've heard google is pretty good! /s

Self-host

Best for what requirements?

Lots of space? Ease of use? What devices? Web access? Etc

I think storj is worth mentioning. You could also look at the list of supported providers for rclone.

I'm using pcloud because proton still doesn't have a way to share folders with other users, so I can't share my holiday photos with my partner there.

Pcloud works fine. The online interface is not the nicest, but it works.

If you need to share with others, trezorit is probably the best option for businesses and Mega is second (and the first few gigs are free)

Nextcloud self hosted if you can. Keep in mind it does require maintenance and planning.

I've enjoyed Proton for several years, except there ia no Linux desktop client. I intend to test installing the client in a virtual machine running windows, and then use shared folders.