It’s massively hard to become even a low level pro golfer. The mindset is very tough too as it’s a lot of thinking time pre-shot, a lot of planning and shot choice.
I used to play 12-14 hours a day, every day… i got down to a handicap of 2 and played a fair few rounds under par on my local course. However, realistically you’d need to be shooting on average a 5-6 under every week to ‘make it’ and even then, you may only make it at the very very lowest level of getting a tour card.
I used to do a fair bit of teaching as that seemed to be my forte compared to playing as i’d often crumble under the pressure when it got down to the nitty gritty.