We use the bfa plugin along with mongo db as storage. due to the change of the operator license for the db to a SSPL license, this application has moved away from its open source roots. as a first alternative we came across ferretdb and tried to replace mongodb with this solution. when migrating our data, we found that ferretdb no longer supports fields with $ dollar signs and dot. without knowing much about mongodb and its data structure in detail. is there any way to adjust the persistence in the code and keep the open source roots?