Revert parallelism temporarily (#38240)
* Revert "Protect ParallelInterface"
This reverts commit cb513e35f9c096d60558bd43110837cbb66611ce.
* Revert "parallelism goes brrr (#37877)"
This reverts commit 1c2f36b480e02c9027d2523746d34e27b39e01a4.
* Empty commit
