Currently, resharding is not expected to be compatible with initial sync for the following reasons:

1. Initial sync does not maintain pinned history. So if the ResharsingCollectionCloner or ReshardingTxnCloner aggregation targets a node that went through initial sync, it could fail with a SnapshotUnavailable error. Similarly, if the ReshardingOplogFetcher aggregation targets a node that went through initial sync, it could fail with a OplogQueryMinTsMissing error. Please see BF-39741.
2. Prior to SERVER-94800 which got enabled in 8.2 (SERVER-106728), the ReshardingRecipientService used to fast count for the documents in the oplog buffer collection to restore the 'oplogEntriesFetched' in-memory metric which is then used for calculating the remaining time estimate. File-based initial sync is known to lead to incorrect fast counts. Please see BF-39456. 

Additionally, this suite restarts the initial sync node which can results in slowness. Please see BF-39454.