Stayman isn't only for balanced 11+ HCP hands with a 4-card major. Two other hand types use it too:

5-4 in the majors: if partner denies a 4-card major (2♦), rebid your 5-card major naturally — at the 2-level with a weak hand (<12 HCP), or the 3-level with 12+ HCP.

Short in clubs: with a major fit, bid as normal Stayman. With no fit (partner bids 2♦), bid on HCP alone hoping partner has clubs stopped — Pass with <11, 2NT with 11–12, 3NT with 13+.