Hi DeutscheGabanna,
Google Drive limits/throttles how many files you can upload per second - this number varies but is very low.
I just tried and uploaded 158 small .md files (the rclone docs) in 58 secs - that is roughly 2 files per second and an upload speed of just 25.123 KiByte/s. I have a gigabit connection and fully tuned settings for Google Drive.
How many files can you upload per second?