Hello everyone, I believe this is my first strategy post here. Quick intro, ive been a slightly losing MTT/SNG player for many years, playing mostly as a hobby. Over the last year I've been working hard on my game and trying to plug the many leaks I had, and seriously trying to learn/understand the game correctly, and give it the respect it deserves. I wont bore everyone with my stats, but I've had a question that keeps nawing at my mind, and was hoping some of the more seasoned MTTer's here could give some advice. Over the last few months, my main focus has been improving my non-showdown winnings, or the red line. Over the last 18000 hands I've played on anonymous tables(Ignition), I have around $3 million chips won non-showdown, with a bb/100 of +13.5, which I think sounds/looks good, but not too spectacular ROI, which is slightly under 25%.
So my question to the more experienced MTTer's is: Over the very long term, should I be focusing on looking to take the non-showdown winnings, or instead look for more GTO or exploitative lines, such as:
instead of raising from the sb vs bb, limping in vs a loose/passive player checking with 2nd pair on a non-threating board, to induce him to possibly bluff/bet a worse hand; when his fold to sb steal is 75%;
So I guess what I'm asking is, over the long term, is it better to hammer on the non-showdown winnings, or look to take more chances postflop vs passive or over aggro players in an effort to extract value from medium strength hands?
Any advice is appreciated, and if there are any good winning MTTer's who might be available for coaching, please PM me.(I hope that's not breaking the rules here). Thank you

Showdown/non-showdown winnings are not a problem themselves. They can be a sympton of an underlying problem. That's what you should find out and work at! It could also be the case that you are doing everything fine and that an unbalance between SD/Non-SD winnings tell more about your players than about yourself (in a table of maniacs, you will always have SD-winnings and Non-SD losses, for instance)

By the way, where and how on earth did you get a 25% ROI? I also want that!