I do not have an Oil cooler.
Will ask the dealer to check the entire system.

 

Did the bike sit for an extended period of time recently? Oftentimes, when a Softail sits for a while, the oil will bleed past the check-valve and fill the sump. The reduced power leads me to suspect that it's wet sumping... and badly. This will also cause overheating and blowing oil out of the breather/oil tank. Have them check it. It isn't difficult.

Just for your own peace of mind going forward, boil some water and check its temperature with your dipstick oil temp gauge. It should read 212° f in the boiling water (or whatever temp water boils at if you are at a high elevation). If it doesn't, you may be able to calibrate it as one would calibrate a cooking thermometer. If you can't calibrate it, you will at least have an idea of how far off it is percentage-wise.

Best of luck going forward.