The phrase "gaslight, gatekeep, girlboss" is a tongue-in-cheek expression sarcastically praising the recipient while not actually endorsing them or their behavior. Kind of like "nice work, genius /s". "Girlboss" started showing up 2-3 years ago and was popularized by TikTok. It was originally used as a casual, semi-ironic term of respect for awesome women, but as Gen Z is prone to do, we immediately covered it in 5 layers of irony and now it can range from a mostly genuine compliment to 100% sardonic, depending on context.
Source: I'm a zoomer who was active on TikTok during the pandemic :P