I don't think they are necessarily all that different. Shakespeare was a pioneer though. He was interested in exploring themes in this unique way. In the English Renaissance, there was plenty of exploration of genre, structure and theme- especially love.
Shakespeare's sonnets are also similar to other Elizabethan poetry in thematic content. They are generally reflections, observations, or commentary on love and related manners. In fact, sometimes poetry from this period is so similar that it can feel a bit redundant. Your statement seems false to me.
If I take the meaning of congruency from a geometry definition, then you are asking about whether Shakespearean sonnets can be like other Elizabethan poetry -- do these various poems share the same features. I would say that your statement above is false. Shakespearean sonnets are very much like Italian/Petrarchan sonnets in that they both have 14 lines and a defined rhyme scheme. Both types of sonnets have a rhetorical structure built into the 14 lines, where the first part(s) of the poem present the situation/observation/argument/evidence and the final part of the poem provides the concluding point. While the Shakespearean sonnet has three quatrains and a couplet and the Petrarchan has an octet and a sextet, there is still the potential for the two forms to be very similar. Both styles of sonnets were widely written in the Elizabethan period and many of these poems share similar themes and subject matter.