Here are some tools and services I'm using to sync data to cloud encrypted to keep data private. I know the best way to keep data protected is to keep it over the internet period, but in today's world of using multiple devices and having a lot of internet services it's a lot easier to do. Any data in the cloud is normally encrypted by me or are zero knowledge where I only hold the keys.
Standard Notes - Encrypted Notes
Standard Notes is an encrypted note taking platform. If you ever wanted the power of Evernote with encryption and privacy, Standard Notes is for you. While the app may, purposefully, seem simple at first glance, there are extensions that can be used with a subscription that add more features to your note taking needs including code formatting, markdown notes, GitHub pushing, and even a hosted blog that these very words are hosted on. All data is encrypted with your password and is synced immediatly with the web app, desktop app, and mobile apps. It's some of the fastest note syncing you'll find and all of it is encrypted for your privacy.
EteSync - Calendar/Contacts
EteSync encrypts and syncs contacts and calendars between your devices. Right now it's meant for synching between Android devices, but there is support for a web app and iOS coming soon. It's based on the DavDroid app which synchronizes between web servers except EteSync uses their server encrypted with a password only you know. It costs $14/year (with a 2 week trial) which isn't a bad price for seemless, encrypted backups of your contacts and calendars compared to running a NextCloud instance or other servers that don't encrypt your data. It's open source, avaliable on f-droid, and has a self-hosting option for those that want that extra sense of security.
rclone - Cloud Storage Sync Client
rclone is a free,open source program for syncing data between various sources including local storage and a wide variety of cloud storage providers that offer APIs. Not only is it a great way to sync data, but it also includes an encryption option where you can encrypt your data with your own keys before it gets sent to the destination server. This lets you encrypt data to any cloud provider so if you have a lot of space with a provider that doesn't care about privacy (OneDrive, Google Drive) you can take advantage of all that space and still protect your data. It's a command-line tool so it takes some playing around, but it's very easy to use. There is also RcloneBrowser which provides a GUI to better view and sync files.
Sync.com - Cloud Storage Provider
Zero knowledge cloud storage in Canada. Not only is your data encrypted with your own password, but it's more affordable than Dropbox as well ($49/500 GB, $96/2 TB). While not open source as some would want, they provide a lot of information on how your data is encrypted and private. The whole package includes a web client, Android/iOS apps, and a desktop client (no Linux) which should be enough to easily transition from Dropbox-like solution to Sync.com. There are also sharing options to share files and support for photo backups as well. The only downside I have is it doesn't have an API or any kind of webdav support to transfer data through other apps, but that's minor for me. The excellent price plus encryption is well worth checking out even for just taking advantage of the free 5 GB they offer.