First grow please support :)

Dont know the value in Lux but if the value is under 100 ppfd its Not god because the shot thinks its night

Make sure you let the meduim,soil,coco dry out between watering,feeding.They need air as much as water.

I would place the co2 bag above the plants so the heavier than oxygen co2 will fall on the plants.

NO don't prune it, what you did is good. you raised the smaller one up. This happens sometimes. Can be a down side to autos as you can't train them as efficiently as photoperiods and topping them. DLI trumps LUX any day. aim fr 35ish DLI near the upper limit of 40 that is used by cannabis professionals. Google Dr.Brucebugbee and DLI for an intro. Hes a wealth of information.

Klux will read differently based on light properties (cct et al). In addition, local variables like atmospheric co2, temperature and humidity further influence what 'your' max DLI is vs someone else's garden. The point is there is no 1 target to hit.. you start in a good ballpark then adjust the light based on how the plant grows. no way around this learning curve. Light is a rate of photons (umol/s) multiplied by hours of operation. Perceiving it as anything by a rate x time is wrong. read up on DLI (daily light integral). Get the gist. it'll help avoid a lot of bad suggestions. consider a pot elevator.. anything to even it out without cutting off growth.. unless you know that growth is irrelevant to the future plans/yield then no big deal to remove it, either. bending/training is another good option too.