We see several tropes over on the DIY forum. People have problem A, but they don't know how to fix problem A, so they fix problem B that isn't broken solely because they know how to do that.
Typically, it is perfectly obvious that the problem is A not B, or only a moment's thought or an easy test would tell them that, but their skill at B pulls them like a magnet to that "solution".
A water heater has a bad element that costs $12. It trips the correct 30-amp circuit breaker, so they change the breaker to a 40A ($11). Later, that trips, so clearly something is wrong. But they change it to a 60A ($11) etc. etc. They know how to change breakers. They don't know how to change elements.
A $15 coffee grinder has a ground fault. This trips their ground fault detector (GFCI/RCD). They could go plug it into the (different) GFCI in the bathroom, but no -- they instantly presume the detector is faulty and spend $20 changing it (the US style is easy to change).
My first thought was "rearranging deck chairs on the Titanic" but that seems to be about a tragically pointless effort done out of lack of awareness.
What's a better phrase for that?