Can't decide between 0 or -10 on 17x8. I have a 2013 with 5100s @ 1.75 and 275 70 17 ko2's. Will the -10 be too much?? I've looked through about every offset thread. I want the tires to be slightly passed the fender but not way out.

I prefer to use backspacing as a means of figuring out how a wheel will sit in relation to the vehicle. For me, it's an easier way of doing things.

We know that the 17" 5th gen wheels have a width of 7.5" and backspacing of 4.5". A 17x8 wheel with an offset of 0 will have a backspacing of 4.5" so it will sit in the wheel well pretty much like the OEM wheel with the outside lip of the wheel protruding just a half inch further. A 17x8 wheel with an offset of -10 will have a backspace of 4.11" so that wheel will be pushed out roughly a half inch more with the outside lip of the wheel protruding about 1 inch further than a OEM wheel. For the look you want to achieve, I would go with the -10 offset but you may have to do some slight trimming to give the tires clearance when turning.

The increase in sweep angle with a 4" backspacing (roughly a -10 on a 17x8 wheel) could be enough to get your tires rubbing with 275's, unless you have your caster angle adjusted forward or a body mount chop.
I'd stick with the 4.5" backspacing (that should be your 0 offset with a 17x8 wheel), unless you don't mind the occasional crunching sound.

Both should work. The 0 will clear a little better when turning, but it is a fairly small difference and should not be a problem if you get the caster set right. 4.1 backspacing vs 4.5. The tires will stick out .40" more with the -10.

How will a 17x8 with +5 offset 4.7 backspacing sit versus stock on a 2021 TRD off-Road?

This will help you visually Wheel Offset Calculator

For reference, I run a 17x9 -38 with 295/70/17 w/ a 1" front level and a BMC and I have no issues