I feel your pain dude. Went through a similiar horror story myself
once.

Now, I simply my joinery. Drawers get the draw lock joint on the router
table. It's very strong (can stand up to kids hanging on the drawer),
and full proof. Norm might turn up his nose at me when he visits me,
but I really don't care.

Don't feel compelled to use joinery that is a PITA. Remember, this is a
hobby, it's supposed to be fun. Just do what gets the job done. It can
be done nice, and your piece won't fall apart on you.

For your project, I'd probably just route a 1/4" dado on one piece,
then make a 1/4" tongue on the other piece. Make it so the dadoed piece
slightly overhangs when you put the corner together, and then sand it
flush. A nice, strong joint in no time at all. No wasted time or
material