When does a campaign stops being fun?

I'm currently in day 1700 on my first successful run ever. My bros are reaching level 30 (lol) and everybody is kitted out and doing great in their roles. How do I encourage myself of starting a new one? 500hrs in the game and I've tried almost every meta build I see in this community in that save. The run never stops being fun and I love the unstoppable force vibe that you enter, specially after the rough company start. My goal is to play other backgrounds like lone wolf, gladiators, cultists and anatomists, the rest seems kinda the same to me. Are those that much different from the plain new company? Enlighten me, fellow mercs!