Resume restore and increase file RW

I’m getting quiet low restore speeds around 50MB/s for the repo which is on a single drive I would have expected closer to 120MB/s if I can the restore and start it again with high number of file reads and writes (if this is possible) will it resume from where I cancelled it it or will it start again I assume it would using “Skip previously restored files and symlinks” also what is the option to increase the file number

All is explained in the docs:

Please note that for slow mechanical disk increasing concurrency can actually slow everything down. You can actually increase restore speed by setting it lower. But feel free to experiment.