MacBook Air start up issue

When I press the power button to start the machine it takes up to 20 seconds for the chime to appear. Even then the Apple logo may not boot in and the bar can go full without loading into the system.

The system is a fresh install on a new SSD and still has the same issue. I’ve tryed a SMC reset and pram reset. Once into the system as and when it allows it will run fine until I switch it off again. Any ideas thanks