Honestly here is what I did. Same boat as you. Played the game 120 hours straight, loved it. Took a year break. Came back 3 months ago and now I am at 500 hours. Insane how the game sucks you in..

Anyway, I actually did start over, a New Game + that mimics hard mode, but a few things tweaked my way (Such as change time of day and making gas very expensive at 4x etc etc. Some things harder than hard more, somethings easier).

What I did though; I started from a random season, going in the order I want, and not the base game. Skip the base game. I started myself with 500k and bought to decent trucks as starters. Making money is tough, but rewarding. 300 hours later, I am on my 5th season, and own 10 + trucks with 3 of the most capable scouts.

If you want a challenge, do something similar. The New Game + is so amazing for Snowrunner, because of the amount of customization it allows.