Depends on your firmware. You can install FreshTomato firmware on these things and enjoy a much better experience with many more features and higher stability.
You are talking about the same Asus that uses proprietary Trend Micro spyware on all its routers? At least it can be disabled, but by default it is enabled and spies on you
Yes. I thus recommend to flash Asuswrt-merlin. It is based on the stock Asus firmware, plus some features and minus some inconveniences as the one you mention.
I assume if it can be flashed it can take OpenWRT too? I like the aesthetic, but IDK I think I'd rather not support them at all if they put spying software on their stock installs.