there is another major difference between LM22675Q MR-5.0/NOPB and LM22675MRX-5.0/NOPB from TI beside the Automotive AEC-Q100 product classification of these SIMPLE SWITCHER®:
the real supplier is either Rochester Electronics, LLC as successor of this obsolete device with DigiKey part number: 2156-LM22675QMR-5.0/NOPB-ND we offer only as NCNR – Non-Cancelable and Non-Returnable parts purchase with restricted terms & conditions vs the actual DK# 296-38092-2-ND, 296-38092-1-ND or 296-38092-6-ND are full franchised parts from Texas Instruments directly with our leadtime being indicated with about 26 weeks.
As both options are without stock at the moment, let me recommend that you check if you can use one of these two alternatives from stock:
MP9486GN-Z as IC REG 100V 1A STEP-DWN CONVRTER from Monolithic Power Systems Inc.
MP9486AGN-Z as IC REG 100V INPT 3.5A SWITCH CUR in Automotive Grade from MPS Inc.
Please review the datasheets to ensure the alternative will work for your application.