I'm in similiar situation.
A private mnc offer me already. I'm OK to work with them but govtech role is really something I wanted to explore.

I know the process cannot be shorten.
Need to do security check, package nego, approval.

I actually don't want to take risk resign without job.

I'm thinking to take the offer. Join next month while waiting the clearance and approval. Which I think need at least 1 to 2 months?
Is this doable?