I read this last year? I dropped it, but now that I'm reading qt bl novels again I want to read it again. I don't believe there was a set ml who followed the mc, and the mc was just world hopping and completing his tasks. From what I remember the mc was gay and always wanted to fuck all the men who fell in love with him but the system prevented him from doing it so he was forced to go along the scripted plot. He always played a role in het worlds. An arc I really remember is where he became a general that was disabled and the fl was a princess, but the prince who he was fighting alongside with was like 2-4 years younger than him. The mc was supporting the fl and the prince was jealous and forced the mc to marry him. The reason I remember this one the most is because he died holding a dildo as the prince went to the new empress to conceive a child because he was told to. I think the first arc was between him and the fl's older brother who he believed always hated him but in the the brother ended up kidnapping the mc and was psychotic and possessive asf and wouldn't let him leave. He died in that arc by taking a bullet that was meant towards the brother. I stopped at an arc where at the end the system was getting annoyed with the mc and wanted to get his revenge by sending him to a shitty world where the mc can't be horny. I remember laughing a fuck ton reading that novel and after crying a lot from these qt novels where the mc dies and the set ml is left alone I think its time to read something to balance the tears.
personally, i haven't read this so i can't confirm if it's the one that you're looking for but try Perfect Destiny. pretty sure the summary fits.