Having the NVMe drive installed should not interfere with booting from SD.
What method are you using to write images to your SD cards? If you don't hear/feel the "click" when inserting your SD, use somethin and stiff to help push it in until you feel the click of the card securing.
What method are you using to write images to your SD cards? If you don't hear/feel the "click" when inserting your SD, use somethin and stiff to help push it in until you feel the click of the card securing.