How much effort should it take to lock or unlock the door? When I rebuilt the car a couple years ago I took all the tumblers apart, cleaned and lubed them (forget what with) and basically forgot about them.

I rarely lock the doors, but do when on vacation. Whenever I lock/unlock either door I hold my breath because it feels like it is going to bend or break the key. Is that normal?

Note: The key turns with ease until the point where it is moving or engaging the mechanism inside the door. The final twist to lock/unlock is where the pucker factor comes in.

Oh yeah forgot an emoji

My "73 is the same. Nothing in the doors has ever been cleaned (except for the windows).

It should be smooth and easy, if not, you will definitely break something. The latches are made of cheap pot metal and the flap is fragile.
Every moving part needs to be cleaned and lubed. Same with the window mechanism, all the trunk and engine pulls and latches. When you get it right, it only takes light pressure.
Tri flow is an awesome lubricant. Wipe off any excess. Extra doesn’t help, it just collects dirt.

Mine was very difficult to lock and unlock similar to yours. I neglected it and eventually the plastic cam broke, so I was unable to open the door from the outside.

It’s not difficult to take the latch out and clean it up/lubricate it. If you have the 700 Tech Tips book there’s a good picture of the important areas to lubricate.

I highly recommend PB blaster’s penetrating lithium grease. I tried a few different lubricants and this one worked the best. I used it when the opposite side started sticking and it worked like new. It works itself into all the tight spots that regular grease couldn’t get to.

I didn't haven luck until I soaked the assembly in gasoline then lightly lubed.

Likely the original grease collected a bunch of fine dirt, dried out, and now it's binding.
Best to clean/soak it in degreaser then lube with white grease.
When done right it feels like a new German car.

Removing the latch is quite easy, unlike a new German car...

I use dawn dish detergent and a long bristle brush. A squirt or 2 of brake clean in the nooks and crannies and then lube.
But you can’t just lube the lock. You have to lube the latch inside the door, behind the outer door lock and the latch under the window crank.

Agreed on cleaning and lube and as long as you’re in there I’d recommend replacing the plastic cam’s 914Rubber minor $$ And since you in there.

Thanks for tips and confirmation. I’ll clean the lock cylinder assembly and the part by the interior lock that the bar connects to and see if it is smoother.