RubberPeen
If those plans come to pass, he doesn't change, it would be a great slice of life kind of thing for his home world while balance it out with action, fighting in other worlds. It's a pretty good setup since you got since it is balanced as long as you don't mix the worlds which will give readers the action, progress, power that many novels do but a break here and their. Many good novels that have the power progression fail somewhat when it is unending, no break for the MC, no stopping, hundreds of chapters. Even readers get tired of it. Many of those novels do well because people read as the are written so its easier to tolerate as sometimes hours\days pass between chapters but in one go in grates. Point is, Do it! All of his plan, without losing himself in it. Go big.
Create automatic machines to recycle all kinds of garbage. Create machines to recycle radioactive waste. Create efficient and long-lasting batteries. Create a machine for first aid treatment. Create efficient and safe electric motors for almost all vehicles or create a filter that reduces CO2 from exhaust pipes.