Do you have a trusted local mechanic that can look at it and answer any questions?
It’s easy to become concerned if you spend time looking up all the things that might happen to your car. The list is endless. And I commend you for looking at you fluids. But the truth is that 99% of the things we worry about never actually happen. If you have your Rav4 maintained in accordance with the manufacturer’s recommended maintenance schedule, you’ll get many years of reliable use.
As to the coolant, it’s entirely possible, even likely, that what you’re seeing is normal. The fluid level in the plastic bottle does go up and down depending on the temperature of the engine and the weather (the ambient temperature). After sitting overnight in your driveway, the level will be a lot lower at 20F than it is on a summer morning at 80F.
Have a trusted mechanic take a peek. It’ll make you feel better.