The SQL Server is only hosting 2 databases currently, and the largest is the one moving, so thresholding SQL back so they share resources shouldn't be a problem. Thanks for the assistance!

Available SQL Server 2019 editions Enterprise Access mission-critical capabilities to achieve unparalleled scale, security, high availability, and leading performance for your Tier 1 database, ...

Both PostgreSQL and SQL Server support some of the busiest transaction processing workloads you can imagine, and it's tough to compare database performance between disparate workloads.