I've struggled with this for the last forty years.

I want to hang something on a drywall wall, and I want to use the
studs instead of drywall anchors. I have the damndest time finding the
studs reliably.

There's the time-honored and lo-tech method of tapping on the wall and
listening for different tones of hollow wall vs solid stud. So, I find
a stud that way, then measure 16" (or 24") on either side, tap there,
and hear a hollow sound. At that point, the process becomes random and
seldom 100% accurate.

I have several electronic detectors and their performance is spotty as
well. I can scan the same spot three or four times and get three or
four different hits over a space of about four inches, too wide to be
a single 2x2. (No, I'm not finding a doubled stud.)

The most reliable gadget I have is also the simplest: a small plastic
horseshoe with a magnetic pointer suspended between the open ends. You
move it over the wall until the pointer moves, at which time you know
you have detected a nail head and are on a stud. The problem with that
is that nail heads are a very small area of a wall and it takes a lot
of systematic scanning to find them.

I invariably end up approximating where I think the studs are, then
punching trial holes with an awl. This leaves me patching lots of
little trial holes when I'm done.

Any suggestions?