Mine does the same. I am taking it to the
shop for the second time in two weeks next Monday. Last week it got a 4 hour update that didn´t
help.
I can unlock one out of 10 times more or less. But never by the passenger door.
Lately it also ramdomly restarts the infotainment with a lot of alarms to follow ( while driving ). Then it changes the "view" in the display at the wheel.
Also, when i turn the car off while in Sport or Cupra mode. It starts up in the same mode next time but only with the sound and the sign on the display.
Gearshift and suspension is back to comfort ( changing in low revs and no blibbing ), it re-engages start/stop and the gears ( f. ex. S1 ) don´t show, only "D".
When pushing the cupra button until the sport mode comes back, all is back in sport.
I will update when i get it back next week. If you find any solution to your keyless access, please share.