Hot take: if <80% of eligible voters show up, nobody wins and the same politicians stay in office for another year, even if term limits would normally apply.
How about instead it immediately triggers another new election and the people who ran previously are not eligible to run ever again
That means the politicians currently in power only need 20% to stay in power, instead of 50%.
It should be mandatory voting like in Australia instead. You don't cast a ballot, you get fined, and voting day is a mandatory national holiday. If you really don't want to cast a ballot, you cast a blank or invalid one.