I prefer having the dash lights off and OEM fuel cut off. Simple as that. Bothers some and doesn’t bother others. Same as a dirty car. Some people are clean and some aren’t.
The other option for the lights . . . which I'm eventually going to do . . . is pull the gauge cluster and disable the actual bulbs.
I don't think you're going to find a solution for disabling or changing the crash detection parameters. So, you're not going to get this problem solved without some give-and-take.
For the record, my 2008 Mustang has the inertia switch that I installed on my 2015 FiST. I don't know when Ford went to the RCM controlled format on the different models, but the inertia switch is not ancient or obsolete tech by any means.