Nobody do that when processing a lot of photos
Two ways, either put the file in the batch queue or use the command line rawtherapee-cli.
No great difference in speed. the cli can be a little faster but I did’not measure.
for cli help use -h option
Why you quit Rawtherapee. when edit is finished, put in queue, Just edit a new photo and so on. When all photo edited, start the queue.
It is faster than a script.