I think you both raise excellent questions for consideration here.
In the middle ages, it was certainly recognised that one did not need to grasp or even strictly assent, propositionally with one's intellect, to every tenet of the faith to be a Christian (distinct from the requirement to not
dissent publicly from it, of course!).
Religious practice, participation in the ritual and devotional life, mattered more.
See:
https://ore.exeter.ac.uk/repository/bitstream/handle/10871/11543/Lay Religion for JMH.pdf?sequence=5
Recent studies have often suggested that ecclesiastical expectations of the laity were relatively low overall, even if some laypeople exceeded these basic requirements. For example Norman Tanner and Sethina Watson have argued that although medieval churchmen had high aspirations for the laity, they were also willing to tolerate ignorance, in a pragmatic attempt to keep as many people within the church as possible.1 This and some other surveys of medieval religion have also suggested that for many medieval Christians, as long as they accepted some core beliefs, religion was more about participating in the rituals than about having a high level of doctrinal knowledge...
This is still the
modus operandi of the Eastern Churches, for example the Ethiopian Orthodox:
"As one of the world’s oldest varieties of Christianity, brought to northern Ethiopia by Syrian monk-missionaries in the mid-fourth century, Ethiopian Orthodoxy has its own distinctive ethos and theology. Within the sacramental theology that governs this variety of Christianity, it is not correct belief, but rather the sacraments that are efficacious, or more precisely, God’s power working through them (Boylston 2012).
What humans can control is being in the right conditions—ritually, morally—to receive divine grace (Boylston 2012: 80). For this reason, rather than correct knowledge regarding the teachings of the Church, staunch commitment to norms sanctioned by tradition and taught by religious authorities are central to the moral self-crafting of Ethiopian Christians and to their sense of religious identity."
(Eliza F. Kent and Izabela Orlowska, The Religiosity of Church Forests in the Ethiopian Highlands)
In Europe, and then globally, the Protestant Reformation of the sixteenth century is the doctrinal upheaval that set
belief ("faith alone"
sole fide) at the absolute epicentre of lay Christian life and identity, to the exclusion of earlier models.
One might view justly that as an historical aberration.