I got good performance with --transfers 3. I just noticed that the google photos proxy is using a lot of ram ! 30% in my 16 gb system doing nothing.
Transferred: 19.841 GiB / 19.841 GiB, 100%, 4.173 MiB/s, ETA 0s
Transferred: 2522 / 2522, 100%
Elapsed time: 2h59m49.1s
So far all good. I just noticed that also trying to use checksum to compare the uploads between google photos and dropbox appears to do nothing, it only checks using size
EDIT: After downloading + 1200 files now I got rate limited again and can't download more. I did ~40 gb in a single day. If there is more documentation about the limits I would like to know. I tried to change my IP but no success
EDIT2: I'm still downloading as fast I can, sometimes i need to stop both rclone copy and the proxy and restart it a few times and then it works, it was glitching but no meaningful messages even with --debug on proxy so I thought i was being ratelimited but I actually think it's just a bug in the proxy itself that probably happens after too many files are downloaded? idk