Key's it appears that the USB S.M.A.R.T. driver is not working on your machine. It is not a problem with the drives, they report S.M.A.R.T. but USB has to be "tricked" into carrying the S.M.A.R.T. data. I know that there is a version of the driver that works on M1 Macs because it is working perfectly on mine under both Monterey and Ventura. DriveDX's developer is not necessarily the quickest responder, but he does respond. Fill out the
support request (there is a different page for other questions) being sure to fill in all the blanks and carefully describe the situation, don't forget to mention you migrated from an Intel iMac installation, and I am confident they will get back to you with a solution.
As to the 10 second finder window I have not experienced that, but strictly as a trial, try physically unplugging your external drives, then reboot and see if it speeds up.
