Has anyone tried the method of normal underwear and a pull up on top when potty training?

Worked well for us!!

It was the method my mom used for me & my siblings after a few days of being entirely naked n free

Well kind of, I used cloth diapers, they do have a stay dry layer but it’s nowhere near absorbent as disposable diapers lol. Since a year old he’s been in cloth training undies - they’re, undies but padded. But in all honesty, when they wee or poo in undies it doesn’t make a “mess” it’s contained in the undies as long as you catch it quick and change the undies quick, it won’t go “everywhere”. So it’s not really needed. Once I stop the diapers I stop the diapers and just focus on the undies, if I need to wash some then I’ll wash some, nbd to me.

It sounds good

We do this when we leave the house but just underwear at home

I did this for a while and to be honest it really didn’t make a difference. I did it specifically for car journeys and if we were going to be out for a while where it’d be harder to have access to a toilet. It didn’t stop her from doing a wee, but for some reason she went through a phase of doing wees in the car every time she got in. I started changing it to pants, trousers, and then nappy on top so if she did a wee she would definitely feel it, and the nappy would stop it from getting on the car seat - worked much better. And then it was easier to make more of a deal about the fact she’d done a wee as it was easier to see on her trousers for her so I could say oh no, we’ve done a wee wee in our pants!

You can find training underwear, they do exactly that.

We use just underwear at home and when we go out we use Huggies pull up training pants that do exactly this they have the wet layer already built in