we used a PCIE SAS card with an nvme drive in a converter over a sata port connected to the SAS card
No such converters exist that I'm aware of, and such converters are largely impossible. There are a few tri-mode (SAS/SATA/NVMe) HBAs and RAID cards, but they generally use SFF-8643 connectors (Mini-SAS HD) to connect to U.2 drives, possibly through a passive backplane. There are no active converters that make a NVMe drive appear to the host system to be a SATA SSD using ATA commands, and nobody will ever make such an ASIC.
If you have a free PCIe slot, you can put a NVMe SSD in it, without involving SAS HBAs. Older systems won't be able to boot off such a drive, but that doesn't prevent an OS loaded elsewhere from using the drive.