Ahsan Allahu ilaykum Ustadh. Is it recommended for laymen to always stay with the safe opinion when there is khilaaf? Including when they have looked into an opinion and truly believe one is stronger than the other? Even if regards something serious, like if something nullifies the prayer or not?

Ustadh AbdulAziz al-Haqqan
If you think 1 is stronger than the other and this is what u truly will face Allah ta'ala with as the truth, then you can follow it yes.