That's awesome to hear you've gotten into shiny hunting! I've really only put "serious" effort into it since Let's Go Eevee, I found that style of hunting very fun, plus it added to the experience seeing the shinies pop up in the wild, then there's the mad dash to get it before it despawns!
Apart from the Red Gyarados in Gold back in the day, the first full odds random shiny I ever encountered was a Rattata while playing Pokémon Silver on the 3DS, 1/8000+ chance! The only thing was, it was at the beginning of the game...
BEFORE you are given Pokeballs! Words can not describe how devastated I was, and to this day it makes be feel a little sick thinking about it!
The next full odds encounter was on Let's Go Eevee, I ran into a shiny Fearow while doing my first playthrough, that was a very pleasant surprise!
After that I had a full odds random encounter with a shiny Sandaconda while trying to complete my Dex in Shield.
When it comes to actually hunting, I've caught a Weedle, Caterpie, Vulpix and a Chansey in Let's Go after obtaining the charm. On Shield it's been dynamax dens with the charm. I have tried MM on an Alolan Vulpix, but have up after 850 eggs, I do want to give it another pop though, I'd consider it a real achievement if I can get a shiny through that way! I also want to try the KO method which I haven't tried before.
Love that there's so many ways to hunt in these games!