you dont benefit transplanting before flower. the plant has already done the root ball so to speak. you'll get some more root growth for sure. but the majority is done & done. you'll feed more. the plants dry out faster. & they grow bro. & they flower. to benefit from a 5gal (which is about a 7 to 8 gal garden container) veg time is your friend.
if you're gonna transplant & veg more. yes ! if you're going to flower, id leave them. feed them right. that's all. get a fan down low. & , to be very clear, container size vs root ball plays a roll in stretch. you want the biggest sneaker you can get type thing. & give the lady time to fill out. crop, tie up, stake, etc.
the plant will grow into the container space. no matter a 16 gal tote or a 2 gal grow bag. only veg time dictates. in contrast , if i transplant from a 3gal to a 50gal & flip. yeah you aint getting mo nugz.
& i know guys that can snatch 10 to 14 dry zips from a 3x3 & a 250w lamp. 5k block of coco. 16gal tote. scrog screen.
listen to these guys. they telling you correct.