I recently looked at MongoDB performance when it can't advance the majority commit point and it accumulates a lot of updates in the WT history store and oplog. (See WT-6776 and WT-6786.)  

It would be interesting to also look at what happens when MongoDB starts advancing the majority commit point again.  Does the draining of the upload and advancing of the stable timestamp create performance issues we should be worried about.

This was listed as optional work that we have decided not to include in the "Prepare to remove enableMajorityReadConcern:false due to WT durable history" epic (PM-1844). I'm creating this ticket so we can come back to it in the future as time and interest permit.