Hello!
I solved my own problem, and I thought of dropping a line in case somebody could benefit from it.
While troubleshooting, I noticed a message "Err 80" in green letters in the viewfinder tiny display. I did a brief research online and found out that that err 80 is a generic error (dang!) and most people linked it to a motherboard failure.
I was getting a little frustrated, so I decided to take a leap of faith and replace the motherboard. The replacement was successful and I now can take pictures again.
A word of warning for all the non technician people (like myself!) attempting to this fix. I fixed laptops and phones in the past, but I must admit that I struggled a little bit during the camera motherboard replacement. Screws and flex cables are tiny and very many of them. I think it's still doable, but I strongly advise to read all the useful guides you can find on this forum beforehand and reserve 2 solid hours to complete the board replacement.