i just got it a sundisk last year. everything been work I had retropie along with kodi on it. I have a portable hard drive aka DV drive connected to the raspberry pi 4. All the Videos are in MP4 and i had no problem. during the summer this year that same error popped up and a few days ago, it appear again
That "error" looks like an SD-Card issue... so get an another SD-card, install the LE, and try it... The fact "that device worked well before" not means is working now too... And an SD-card isn't something expensive or hard to find.
That "portable hard drive aka DV drive" have own power supply or draw the power from the USB connector? If powered from USB, could be a power source issue (if without that hard drive always booting fine). For external HDD never recommended to be powered from USB.