I see three potential doomsdays scenarios:
- US invades Greenland, Canada, or another neighborhood
- Escalating trade war. US tech giants are forced to boycott its international userbase
- Massive forced USD devaluation shattering the financial markets
And of course none of the extreme, but the usual chaos.
Honestly the best prep will be done outside the US.
It’s within possiblity the us owned foreign bank account would be frozen or seized with a hostile action.
You can prepare are long term food insecurity with planing gardens/farm as well as stockpiles of shelf stable calories. Rice is a fav of mine since 50# is cheap and long lasting.
Other than that there isn’t much useful that can be done. The us is energy self sufficient so not likely a challenge there.
You could take a serious and rigorous look at your health as there may be a significant problem getting medical equipment , doctors, and treatments. Getting healthy and getting strong gives you flexibility in your plans.