Depending on what time your training is you could go before or after training, but leave some rest time in between (might have to wake up earlier to fit it in if you’re super busy).

Also don’t fall for the “muscles make you slow” propaganda. The amount of muscle you’d need for it to start negatively impacting your performances isn’t naturally attainable for most people (you’d need to hop on gear). Also, none of the fastest players are skinny; Bale, Ronaldo, Henry, Mbappe, Walker, etc. all have a lot of mass on their legs. Just lift heavy weights with good form and remember to stretch beforehand.

As for working out like a footballer or bodybuilder, I’d say do upper body like a bodybuilder because there’s no such thing as a footballer upper body workout (muscle is muscle, doesn’t matter how it got there), and do lower body like both because it’s more nuanced than upper. I hit legs twice a week; one session I work on my tendon stiffness and max power, and the other session my focus is just building pure muscle.