My suggestion is American Standard with VorMax flushing system. I prefer the VorMax plus that comes with a built in cleaner stick so every time you flush, it cleans the bowl, but it does it without the chemicals ever getting in your tank and killing all the seals. https://www.americanstandard-us.com/vormaxplus
The flushing system itself is superior to anything I have come across, the cleaner is a great bonus. You can buy them at HD or your local wholesalers too. Really good products and a company really focused on toilet advancement.
The non wax toilet seals are great, I use them myself, wouldn’t think of going back to wax.
One piece vs 2 is purely preference and I’d sure as hell leave the Glacier Bay toilets right where they belong, on HDs shelf.
One thing you should know about if you don’t is this awesome product from Oatey, called liquid lock. You turn off the water and flush the toilet, then add the packet to the bowl, it gels up all the water in the bowl and trap so you don’t have shitty water dragged through your house. Buy 2 and use them, it’s worth it.