I'm getting ~190k base and ~240k annual package outside - not even mid-level management yet.
In general, what kind of position/rank would someone in mid-tier civil service/SB be in, for this kind of salary? Thinking about whether it's possible for me to move into SB next time for that stability.

you cant have your cake and eat it too

I dont see the point to go SB for stability. If you are getting 240k outside and has good work life, just stick to it till retirement. There are costs to stability also..

Ya agree. Just spend like you earn 100-150k and save or invest the rest, then just work till you retire or lose your job.
Stability is only an issue if you spend like you earn 240k

Before we digress from thread topic and have someone worrying about possibility of joining civil service with current pay of 500k... I agree these aren't the usual range for average performers in average schemes. Probably top 20-30% performers. I am average farmer (in tier 3-4 agency) and fall short of these ranges but I know my sister and her circle of friends falls within the range. They are mostly non scholars or average scholars in the so called tier 1-2 agency (which is debatable but e.g. EDB, MAS, MFA..). I hope this thread does not give unrealistic expectations for the average farmers..

Wow got tiers? How to know and select the correct one?

MAS/Govtech -> EDB -> MFA -> the Rest

Not official, but my sensing is:

Tier 1: MFA, EDB, MAS
Tier 2: MTI, Govtech, Mindef, ESG
Tier 3: The remaining ministries
Tier 4: Most statboards, like NLB, PA, NParks....

govtech is tier 2??

I can guarantee you that unless you have a very niche skill or intimately know someone in very senior management, you will not be able to simply switch to civil service at this mid/senior level.

you think they will suka suka want to get someone from outside? then the social compact that they have with their employees on years of service/loyalty/progression gets chucked out the window, not to mention the pathway for scholars.

Everyone will want to work themselves up in the private sector and then jump to the civil service for stability once they hit a high $ amount otherwise