Dunno about you, but losing 20% of my electricity supply is an annoyance. I just don't run the clothes dryer and hang my clothes on a rack instead.
(And yes, I have solar + battery, and have lost 100% of my outside electricity supply on a half dozen occasions since having it installed, and my actual response has been to not run the clothes dryer.)
That would be the situation in an integrated/"smart" grid. The grid could tell your washer/dryer to defer or worst case shed their load.
In the grid we have, where most people don't have batteries, nor a way to react to (or even perceive) network-side load shedding commands, you get rolling blackouts at best, and brownouts, damaged devices etc. at worst.
That's the point I'm making with my second paragraph. I'm not dependent on the grid. If we get into the situation you're describing, I just throw the main breaker (actually don't need to do that, the inverters switch over automatically) and my home generates its own electricity. It doesn't quite cover all my usage, but it covers all my usage except the clothes dryer, so I just don't run the clothes dryer.
It's true that there are tragedy-of-the-commons situations where not everybody has a battery, but it's also true that there are higher-level but subnational entities within the U.S. that have invested significantly in renewables + battery storage. This chart of where electricity comes from on a state-by-state level is illustrative:
https://www.nei.org/resources/statistics/state-electricity-g...
California, Connecticut, DC, Idaho, Maine, Massachusetts, New Hampshire, New Jersey, New York, Oregon, Rhode Island, Vermont, Virginia, and Washington are > 95% renewables + natural gas, all of which is produced in North America. If it comes to the point where it's "keep the lights on or sever ties with fossil-fuel states", I'd bet that they choose the latter.
(Note that the table kinda refutes your point anyway: the only states that are > 1% dependent upon oil for electricity are Alaska and Hawaii. Other than natural gas, which is largely produced domestically [1], the other big fossil fuel source is coal, which is also produced domestically.)
[1] https://www.eia.gov/energyexplained/natural-gas/where-our-na...
If a country were in your individual position, I'd definitely call that self-sovereign, but I don't think that's how "80% self-sufficient" would actually look like. (I don't think that 20% of most countries' consumption is entirely discretionary, for one thing, whether measured by peak or average load.)
At >95%, it's probably a very different story. At that point, you basically turn off your aluminium smelter and you're good :) (And note how GP said "renewables", which gas isn't.)
And my point really isn't about oil specifically, it's about GPs "renewables increase sovereignty" thesis in general.