I already tried this out and the LDR worked.
https://youtu.be/XwJQJnY6iUs?si=pf1hsxh9qAem_sNy
Also I tried to upload the same code with the LDR connected through the breadboard (and not soldered) and it also worked.
The only think that remains a possible cause of the problem is the soldering work.
Also sorry for the misunderstandment ("welding" instead of "soldering") but I thought it was the right translation from Italian 