This may or may not solve your problem. I also used the double wax rings before - wrong solution. They will eventually shrink and you'll have sewer order/air leaks. This kit worked for me because we had an existing flange, but the tile had raised the level above the flange, i.e. flange extension. If you have screws to mount it the slab (or perhaps, can use concrete screws), I'd think that this would work to bring your flange up to it's proper level (maybe 1/4" above your finished flooring). There are different sizes available.
1/4 in. - 1-5/8 in. Toilet Flange Extender Kit
There's other options out there. Look up "Toilet flange repair kit" on a hardware/box store website. Don't worry, it usually not that hard to fix. If you have a broken cast iron pipe in there, you'll have to do some more research, i.e. more complicated.
Oatey also makes this twist in thingy. I don't like 'em, but it might be your simplest solution. I prefer something mounted solid to whatever floor base there is.