I have no experience benching 300 lbs, but I found the body weight fitness group on reddit a few months ago and it's made a huge difference progress-wise and with my overall outlook on working out (still can't bench 300lbs... yet.
).
The foundation of that program --- progressive overload, big compound moves as opposed to (for example) annihilating your biceps with a million curls, 'resting hard' and not needing the p90x-like 6 day routine --- has all really clicked, including a few trainer channels on youtube, at least for my beginner/n00b self who was stuck in the 90s marketing campaign of working out (the few times I've actually tried to).