About the ramdisk for temp files:
I played around a bit with replacing temp files for encryption/compression/upload with in-memory buffers. In most cases this is possible, except when the backend only supports file operations, or streaming is disabled. In my tests, I didn’t see the speedup I expected (compared to SSD), but maybe that would help on systems with a hard disk and enough ram.
The only struggle is deciding how big these buffers can be, to prevent running out of memory on low-ram systems.
If you think this is worth pursuing, I can do more in that direction. It would obviously require lots of testing that nothing breaks.
It was also suggested on GitHub to use Zstd as a more efficient compression algorithm, but that would require integrating a new compression library.