Question about coolant. I have red coolant in my 2015 Frs
 

So ive had my 2015 frs for 2 years, (some background) i recently started putting A LOTTT of miles on it like 200 daily 5 days a week, Car is running great everything good, temp doesn’t fluctuate it’s a 2 hour drive and it usually ends off at like 35-50% on the temp gauge. I just became worried because I saw another brz with blue coolant. So I searched it up online and it says gt86/frs/brz should run blue coolant. Well my car has been running red coolant for 2 years and levels are always fine, temp is good, car itself is good. Should i worry bout it and flush it to put the correct (blue) coolant? Or it don’t matter ?

If your car's temperatures are normal and you've been using the same coolant for 2 years without any issues, switching back to OEM doesn't seem like a problem if you want to ease your mind.

The problem with the wrong coolant is not that it won't cool the engine sufficiently (plain water will happily do that), but that it will cause corrosion in the engine, cooling system, or both. I would recommend putting the correct coolant in with as thorough of a flush as you can.
Also note that the color of the coolant is typically a decent indication of its compatibility, but not an absolute one. Make sure to use coolant that is compatible with the engine (sadly coolants don't use type certification/specification like oils (engine, transmission, etc.), so it's hard to recommend anything specific other than "go to the manufacturer website and check compatibility with your car").
My owner manual (2018 BRZ) just says: