I would like some advice/insights on corpcomms job in various sectors, namely in GLCs, and private sector. Would also want to hear about Investor Relations jobs.

Can forum users here share how corpcomms work is like in GLCs like Changi Airport, Singtel, Ascendas, and MNCs; and whether my background/experience below would be useful?
How is the pay like? Job scope?

As for Investor relations job, would they want someone like me with corpcomms background looking for a career switch? How different is investor relations from the usual corpcomms work? What would the pay be like? Is it extremely demanding, in the sense that public listed companies would always push for their IR officers to promote and say positive things abt the company; and then when share price drop are these IR guys at risk of losing jobs?

some background :
I graduated with a comms degree from local uni. I have been working in the corpcomms dept of a major Stat board for 3 years plus now. I handle mostly media relations work (press release, announcements, media events, day to day media queries and forum letters etc). I am comfortable with the fast pace environment. There is always lots to do and we need to prioritise our work. I do not fancy moving to corpcomms in Ministries as I've seen for myself how they work.