I've been experiencing issues with 2.4Ghz bandwidth. It's very unstable and often extremely slow. 

Our internet connection is 300/36Mbps and I can easily achieve those speed when connected to 5Ghz, but 2.4 is a disaster. It often disconnects devices and takes about 30-50 seconds to reconnect often stating that no internet connection is available (while 4Ghz network works perfectly fine) and speeds achieved drop to ranges of 0.5-2Mbps. 

It gets to a point where I had to forget the 2.4 ghz network as I am unable to work!

I know that my internet is stable as 4Ghz achieves full internet speeds. 

The router is updated to the latest firmware. 

There is nothing blocking it especially considering that 4Ghz works flawlessly