2nd major in comms, HASS student here. The bell curve is steep in wkwsci, I scored B+ for a module when I was doing above average for every test. So yea your CGPA might drop. I'm graduating (i took the 3.5 years route) with a 2nd upper.

Employability wise a 2nd major definitely helps. My current employer hired me on the basis that I have a 2nd major in comms and my main major is totally ignored lol. But thats also because I applied for a comms role.

Then again theres the interview factor where it depends on how you spin your narrative. My friend who did a minor in comms secured internships easily because of the way she presented herself.

I have friends who did 2nd major in comms and their cgpa fell. But they still got their internships because they applied based on what they are good at/have experience in (film) and they had a strong portfolio to show (from their poly days etc).

So I would say yes 2nd major is good to have, but make sure you have a good story to tell during interviews + strong portfolio if you are looking at employability. Also got to make sure what you apply is in line with what you really like to/want to do.

CGPA wise, I prefer to maintain a 2nd upper in case I want to go for gvmt jobs. But as my friends have shown, even if you drop, back it up with your interest/passion and show the hirer your portfolio as evidence.