You can still make it non combat or mostly non combat.
However that could be a challenge.
You can add combat as well and non combat , a healthy balance of sorts. However in the case the world and and environment will be key to help this. Along with having character to meet or interact with.
There are mangas and some anime that I have see do something similar, but it has been a long time since I last saw em.
There is also the mech designs and setting that need to be considered.
How will long distance transportation work? (Will you ride the mech on the inside or from outside?)
Are interaction while on/in the mech different from not riding?
What are the different areas and regions you can explore and what are the different customs and enemies in each?
oh my you give me hope! 😄comments are spot on, perhaps a balance between combat and adventuring would be great, and better interaction wit the Mech, I could totally imagine a system where you climb the Mech for transportation, the plot could revolve around the illegal mining of the ether crystals, and you fight evil corps to free the slaving robots, man you inspire me so much! hopefully I can find time to work on this soon! 😄