1500 mmr new to carry trying out jug any tips?

so i got to 1500 mmr as a support/offlaner but i started playing with a group of friends and realize as a carry i do really well. but because im 1500 mmr i know i could be doing better.

as jug my build goes agi mask, manastone into hp mp regen ring for sustain, followed by phase boots then onto battle fury, i average a 13-16 minute battlefury. from there i get basher and then start helping in teamfights when im close enough, keep side farming till i get scepter and i start actively going for kills. some people say i should be more active in teamfights but alot of the time i realize im no good till i get basher, and often im targeted first, so having the stun is key.

ive seen other people saying battlefury is trash and i should get molnijr instead but as im often the target i feel i need the hp regen for sustain to really do much

so am i building right, should i be joining more fights even if theyre away from farm? should i buy a tp scroll or two to help team fights what exactly is my role as a safelane? ive only been playing the role for a week, and while ive had a really successful streak i know i could be doing better. any tips would help.