I helped one of my clients swap from their "bespoke" solution (dodgy bash scripts and an S3 bucket) to Snapshooter which made our lives a lot easier. Looking at Backupsheep's website it seems like it is very similar to Snapshooter, so I think that would be your best replacement.
I've never used it personnaly but you can take a look at duplicati (9,5k stars on github), it seems to have a nice GUI too
Simon here, founder of SnapShooter which sold to DigitalOcean this year.
Bilal made a good product with BackupSheep, it was released about a month after DigitalOcean. It's sad that he has shut it down.
We would be more than happy to help you get setup on SnapShooter, most of the features from Backup Sheep translate to SnapShooter