I'm a machinist main that personally really /really/ dislikes bard gameplay.

Keep trying out rotations and openers on training dummies. Overheating early can be due to high skill speed (which current tier gear is FULL of).. You ideally don't need to hit Cooldown even once between OH Wildfires.
Every buff works in 60 seconds and you will be hitting buttons in the exact same order AS SOON as they come off cooldown during the next Wildfire, as long as you do a correct opener.
Hotshot is applied in the downtime after Gauss Barrel falls off.

There's plenty better tips and guides online but this is just the basics