Recently, I’ve migrated my personal backup from Backblaze Backup to B2 (an online S3-style file storage, also by Backblaze).I’ve heard of Arq Backup for a few years now but had not tried it yet. Being a native macOS app, it has a very nice UI and meets all the requirements mentioned above.

For the record, I am writing down other softwares I have considered and why I did not use them. Note they are all server-oriented and need to be scheduled using cron or similar software. All of them also support encryption.
borg

A fork of attic, which was known as the holy grail of backups. It supports compression, block-based incremental and is open-source. However, the only remote backup it supports is SSH. Rsync.net provides an attic-specific package for $0.03/GB/month, which is considerably higher than B2’s $0.005/GB/month.