Problem solved.
Although the reference manager picked up on the new extension loaded by the NI package manager when I migrated the project - it was evidently using the file location on the old machine. It was necessary to delete the reference and point it to the newly added extension.
My bad.As far as comparability of VS2022 and MS, the verdict is still out while I debug my "upgraded" project. The VS Help did a fine job of pointing out the error of my ways. Another lesson once learned and then forgotten - sorry.