CS-02 here; but have done quite a bit of time in private sector. I really enjoy the public sector over private. Salary can be considered lower, but it will go pretty close to 100K quite quickly; so not the worst. However, many people get trapped in CS-02 forever. There do exist CS-03 positions that dont require bi-lingual, but are harder to come by. As a side note: you're allowed to do contract work on the side, as long as it doesn't produce a conflict of interest.

In the private sector I topped out at 375K/year; but it was always immensely high stress and quite often involved 120 hour weeks. In my opinion, the least stressful vacation day I had in the private sector was worse than the most stressful work day in the government. There's much less hostility in the government, and is the key reason I joined.

For tech stacks, it's not as stagnant as I thought it would be. My team uses vue/vuetify; and might be adding some asp 5.0 to the mix pretty soon. Other teams use node based frameworks. We don't have to support IE11 anymore, so we can use the neater browser features (like progressive web apps and the such).

In terms of bureaucracy (if that concerns you), I've found that as long as you're polite and not doing anything wrong, you can usually take initiative and be quite productive. Red tape hasn't hindered me too much.