Good thing she doesn't appear more, author knows what they're doing when the focus and plot of the story solely revolves around business, why even bother with gf stuff, she'll most probably appear, if author needs filler for next plot.
This will honestly ruin the flow right now and I have a feeling she'll appear more when talks of his marriage are there because she herself is from a very affluent family again strengthing our MC reach, there was a mild introduction about her(when in college) and her family( grandpa and his secretary panel).
For now Company-chan is the one MC love and is loyal to her, why do you want a third wheeler between MC and company-chan.
I wish the girlfriend appeared more. Like why doesn’t she attend events and what not. Does they even text each other ヽ(`Д´)ノ