Bide one’s time
(PW) wait patiently for the right opportunity
I’m just going to bide my time. I know that eventually a position will open.
(yourdictionary)
Wait for the opportune moment, as in The cat sat in front of the mousehole, biding its time. This phrase employs the verb to bide in the sense of “to wait for,” a usage dating from about a.d. 950 and surviving mainly in this locution.
(freedictionary)
bide one's time
to wait patiently. I've been biding my time for years, just waiting for a chance like this. He's not the type just to sit there and bide his time. He wants some action now.
bide your time
to wait patiently for a good opportunity to do something She was biding her time until she could get her revenge.