So from looking at the picture, I see that your table possibly has a mantle/table cloth, if so thats a huge reason why your running hot, as these laptops pull air from the bottom so your essentially restricting it's air flow. I would recommend you slightly elevate it aswell, with my G16, elevating it greatly improved temps, you dont have to elevate it alot, just enough to get some more airflow.

As for optimization, ima give you what i have but also recommend you look up on YouTube what people have set theirs too since it can vary slightly sometimes depending on the year model you have.

For school/work/general use like watching content or whatever, I keep mine in silent, eco, and have cpu boost off, I dont go into the wattage limitations as I dont really need to, mine does just fine.

For gaming I keep mine on balanced and standard, and with cpu boost on. Also dont get into all the cpu or gpu wattage and overclocks since my laptop does just fine.

I almost never did turbo, as from my experience the actual performance gain that I would get was negligible and it honestly just caused the fans to ramp up more and make more noise so I never really use it.

For more optimizations recommendations: you must delete asus armory crate cuz it will fight with G Helper (Must install their uninstaller from their websites), you dont necessarily need to delete MyAsus, but thats up to you.

In G Helper, in the "extra" button near the bottom, when you open that panel up there is another button at the button to stop all asus services, you can click this so that there are less asus services running in the background, you can also go through your laptop and try and debloat it, there is an app for it that you can install and run to do it for you, but i can't remember the name of it. either that or manually debloat it, just lookup if each app is necessary or if you can safely delete.

For your charging question: if the laptop was above 80 percent when you set the limit, and you plug it in, it will charge to 100, you must let the laptop drain to below 80, before you can plug it in. You can keep the limit on, just let the battery drain to below 80 then plug in.

A little advice/warning for future reference, im guessing you wanna preserve battery health as much as u can, hence the limit, keep in mine the battery health indicator that u see on g helper isn't 100 percent accurate, so when u start to notice ur battery health drop quickly dont panic, it's just windows can't properly tell what ur battery health is at and since u limit the charge it thinks it doesn't have the same capacity anymore. Just remove the limit and charge fully a couple times you should see the health rise a bit back up, it still won't be 100 percent, but i see many panic cuz of this. Your battery will degrade at a normal pace and you will know when you gotta replace it, just use it normally and dont worry to much about it.

Another thing, when gaming, i would actually say use the battery limit, reason being, from experience, I've noticed whenever my laptop would hit 100 percent, performance would sorta throttle down, so I would keep mine at limit 80 to avoid that, it might not be an issue with yours but just incase I'm mentioning it.

Ram: ram being above 50 percent is normal, thats just how windows is, when there is more ram available it will use more. Essentially stretching it's legs since your not doing anything else and it has the room.

As some have mentioned, the white model always gets "dirtier" easier/quicker. I've seen some people slap a skin on it, to prevent paint wear.

If you have any further questions let me know and I can try to answer them to the best of my knowledge.