Agile Maturity Models in some cases are used to tell team members their practice of Agile is immature, in a judgmental way that infantilizes them as opposed to having an adult conversation among peers. This violates the principle of respecting people, that is central in Agile.
They also use a gap-thinking between the current state and an idealised future state that implies the existence of a rigorous definition of Agile, which is a paradox (see for example Rigorous Agile 
by Martin Fowler).
And Agile Maturity Models ignore context and circumstances and have a linear definition of both maturity and progress. While Agile is context-dependent and pursues fitness-for-purpose (link to original picture below) .
Barry O'Reilly discusses here Why Maturity models don't work .
Maturity Models Maturity Model (extended from John Cutler original)
The alternative to Agile Maturity Models is to let people volunteer conversations around their Agile adoption that create awareness around opportunities for improvements. This is based on invitation and not an imposition. It shifts from measuring people's performance to discussing powerful questions and offering support. The former comes from a place of control and lack of trust, the latter from a growth mindset and behaviours.
The alternative to Agile Maturity Models is more like a volunteer self-assessment where coaching and mentoring are offered, not imposed.
The self-assessment focuses on the potential for improvements and progress instead of criticizing, is approached in context-aware ways (the result is not an absolute measure but a relative one), and recognises that things can move in a non-linear way based on opportunities and personal preferences and learning style. The human element is central, and a present-thinking (what we do know from where we stand) replaces a gap-thinking toward an idealised future.