For a long time I've tried to get a good RPG setting going for BT. I know there's an already written RPG for the game but tbh I don't really like it. For a while, I thought about making a bare-bones RPG myself that used the same base mechanics scaled down, but I found it was just too crunchy and slow. Now, I'm thinking that since the game will get very crunchy and simulated once it steps into mech combat, it can probably be narrative and story-based for the out-of-mech sequences. Since my favourite RPG is hands-down Blades in the Dark, lately, I've been thinking of writing a Forged in the Dark system game for battletech.
This is getting pretty niche so I'm not sure if I'll find enough people who play BT and know FitD well, but I'm curious if anyone in here knows of an existing FitD build, or other more narrative-focused RPG, that would be easier to adapt to BT.
If you want a system that is more narrative and less crunchy, you can give Lancer a shot. Core book has a free edition, which is linked. It's a little more generic mech than explicitly Battletech, but it has a similar feel.