I just ran my sync from OneDrive to GoogleDrive and it had the usual speed around 12 Mbyte/s. I use my own client ID on both remotes. The only tuning parameter is --checkers=16, the rest are defaults (that is no --tpslimit, --transfers=4 etc.)
I have found that it is best to stay just under the OneDrive throttle limit all the time, and that corresponds to the rclone default settings in most situations. This is especially important with respect to transfers. OneDrive Personal will only do 4 transfers and may slow down if you try using more. You will sometimes get better performance by 16 (and even 32) checkers if your only do it for a limited period each day (I have a 15 minutes backup job).
Your job above has --transfers=5 and that may have triggered the OneDrive throttling, it typically cools down in 24 hours with no (or very limited) activity. Additional retries or load testing to troubleshoot the already active throttling will only make the throttling worse and extend the cool down period. The cool down period seems to affect all clients using the same Microsoft account. 
I don’t think the --user-agent tip will help you - it is aimed at OneDrive Business (SharePoint).
Some other tips instead: I use --progress --stats 5s to find the optimal settings for my jobs. You may want to tweak --multi-thread-cutoff and/or --multi-thread-streams if you have a high proportion of files above 250MB.
In the above I have assumed that v1.55.1 performed well for a while and now all of a sudden it doesn’t. If your issue started immediately after an upgrade to v1.55.1, then it would help to know which version you upgraded from - and whether a downgrade to the previous version helps.