Dear Hope,
Peace
Not necessarily Shi'a bias.
Only the interpretation that links 'wa'hum' (plural) to a particular personality (Hazrat Ali) and to the story of a ring being passed to a beggar during ruku (bowing), is certainly due to Shi'a bias and is based on Islamic secondary sources exclusively.
Linguistically, the 'wa' can be used in this way to express the conditions or circumstances under which a particular action takes place ('haal' clause). Hence you may note the reference to a prefixed conditional / circumstantial preposition when describing the 'wa'. The 'wa' is followed by a pronoun and a clause or narrative which describes the circumstances.
So for example, if I say in Arabic 'wa'fooji'a wa huwa ya-qta'ul-hatab'a', I would mean 'He was surprised 'while' he was cutting wood'. The conditional / circumstantial 'wa' (while) would provide the prefix to the circumstances (cutting of the wood), in which a particular action (being surprised) takes place.
So in the case of 5:55, it can be argued that the conditions / circumstances in which believers establish salaat and give zakat (actions) occur ‘while’ believers are in a state of 'ruki'un'. Ruk'iun as a primary connotation carries the meaning of 'bowing' but more appropriately in this context, carries the nuance of 'humility'.
However, there is a huge leap of faith from this possible linguistic perspective to linking it to a narrative concerning Hazrat Ali, which is clearly refuted by the use of a plural context which I have already respectfully shared in my post above.
I hope that helps, God willing
Joseph.