Yes, a .22 is very viable for self defense. I'm 74 years old now, but I've been carryng a .22 of some kind since I was a teenage gang member in D.C. In January of 1969, I used a .22 derringer to defend myself against a guy tying to bash my head in in an ally in an attempted robbery. They are right, the .22 has no one shot stop capability. I had to shoot him twice. The first shot was very close range, maybe 2 feet after I had ducked his first swing. The shot made him hunch up a bit with a grunt, and he went to swing on me again with the steel bar in his hands. The second shot was maybe a foot from muzzle to belly, and I don't know what it hit, but the effects was instant. He dropped the bar, doubled over and went to his knees, then toppled over on his side in a tight fetal position, screaming in obvious pain. I ran like heck and got out of there. Gun used was a Svenson 4 aces in .22 short.
In April of 1988, on a backpacking trip in the Shenandoah National Park 17 miles south of Front Royal Virginia, I used a mini .22 revolver by North American Arms to run off a wacko invading my campsite at night. One warning shot and he ran faster than Usane Bolt at the Olympics. I broke camp and made tracks the other way.
On Memorial Day 2017 just after dawn, at a very deserted interstate rest area in West Texas, two young guys tried to carjack me, but changed their minds when they realized that they had brought knives to a gun fight. They ran off back towards the river and Mexico.
I've used a .22 my whole life. I've tried other guns, but just didn't like them enough to keep them. With a .22 I can afford to practice thousands of rounds a month way way cheaper than I can afford center fire. And growing up in the 14th street corridor of D.C. in a slum apartment, I saw lots of violence as a kid. I saw two guys get. in a fight one night, one guy pulling a strait razor, the other guy pulling a cheap German RG .22 revolver, and killing the razor guy on the spot. shot him 4 or 5 times real fast like poppoppoppop and razor guy fell back and thrashed around a bit gagging up bright red frothy stuff, then went very still. Dead as a door nail. In the 1960's, the RG.22 revolver was one of the most popular guns on the street. Cheap, reliable, and you could toss it in the river with no regrets. The Italian Galessi .25 auto was also a popular gun. By the late '70's, the Raven .25 was getting popular as well as the RG.22 revolver and FIE titan .25. They all killed people and defended folks who didn't read gun magazines.
One note to the OP; while a .22 will work fine of you do your part, use only a revolver. Ruger LCR, S&W J frame, and use CCI ammo. I don't know why, but the 'dud' factor seems to shrink a ton with a revolver. I don't know if it's the hammer delivering a heavier blow to the rim or what. Just before the pandemic, I bought a new Ruger LCR in .22lr. To date its had 4,865 rounds through it without a single malfunction. Something I have never experienced with a semi auto. My wife has a S&W 317 since 1998, and she practices regularly, and has zero malfunctions.
Go get a .22 revolver and practice and practice until you're so familiar with it you can shoot it in your sleep. Get to where you can keep a tennis ball moving. You'll be good to go.