Freenas backup to Backblaze B2 insane number of Class C transactions

Does anyone know a good fix for Freenas using an insane number of Class C transactions when backing up to Backblaze B2? I have a customer who was charged $1.26 for storage and $37.96 for Class C transactions last month. If I did the math right that is just under 320k transactions per day to backup 275GB of data.
I found a mention of adding --fast-list to the config here, but I don’t completely understand how to make that edit and get it to work. There is also a mention of it here, but I don’t see a mention of rclone in that file. It sounds like the option will get exposed in the gui in 11.3, but that won’t be released for 3 months.
I’m thinking of using Cloudberry to do the backup if there isn’t an easy fix for Freenas.