My main dataset that I back up with restic is around 11 million files or so, and fluctuates between 8-15TB of source data. I think I've run into similar issue

My main dataset that I back up with restic is around 11 million files or so, and fluctuates between 8-15TB of source data. I think I've run into similar issues testing out various backup tools too, but have settled on restic for now since it's been the most reliable. I'd definitely recommend trying restic again if it's been a couple years. Somewhat recently they made some nice speed improvements. It used to take me several days to do a forget+purge on my restic repo. Now it takes only a few hours (less than an actual backup takes). How many files are you backing up? I found the biggest issue for me was that almost every tool tries to keep the list of files in memory, so once you get into millions of files - it starts to require a lot more memory and can crash on low-resource machines.