Coolant level is low, needs topping off. It can be hard to get all of the air out of cooling systems the first try, sometimes it needs to heat cycle where it expands and contracts, sucking in the fluid in the reservoir.

“Runs out of oil every 6.8k miles” means what, exactly? The low oil light comes on?

Assuming it is a 5ish qt capacity, that is about 1qt per thousand miles if it were completely out and destroying the engine by the end. Burning that amount may be annoying, but is within the realm of what most manufacturers consider ok and is also why you should regularly check your oil level and top it off when needed.

Open your owner’s manual in the glove box, it tells you exactly what oils you can use.

That’s like 40k miles, hardly a big deal if you’re not aggressively using your brakes a lot.

Drain and fill will only change about half the fluid in an automatic transmission, as the other half is trapped in the torque converter and other areas.

If you’re willing to spend the money for a flush, go for it, that’s the best option, but not the only correct choice. If you want to save some money, do the drain and fill. Both will work.

You’re already doing more maintenance to your transmission than most people who still somehow drive without too many issues, so dont worry either way.