The other thing I try to do that I didn't think of in the other reply is not mixing mods together.
Most major tech mods are balanced for standalone play. They merely contain integrations with other mods as convenient curiosities. So when you mix overpowered machine from mod ABC that is regulated by some restriction, and combine it with machine from mod XYZ that trivializes that restriction, the progression collapses and it's boring.
Some people like that. I try to avoid it.
Some might wonder what the point is in playing with all the mods if I don't actually use all the mods. And my answer is I do, but all separately in parallel. I like being a botanist and a thaumaturge and a blood magician and an astral sorcerer and a pressure mechanic and a mekanism engineer all at the same time, but like... in shifts. When I get bored of one I put it down and advance another. I want to feel like I've mastered them all rather than cherry picked the best parts of each. I get all the variety but few of the problems.
All of this context switching means I waste a tremendous amount of time, but it does make the game last longer. But not too long.
Also, in coop, it pays well when players specialize. I do this magic, you do that tech, etc. Share one or two things in common, but also be different. You might end up wickedly out of power balance depending on which mods you picked to specialize in, but imo that's not really the mark of success.