I see what you are doing but it needs to be opinionated to at least to the extent of sticking to core values.
As a extension of that, I wouldn’t expect features to be carved up to convert people to become Monzo Plus customers. Similarly the optics of Monzo would change if you started offering Premier Banking services for people a certain level of income, or savings of a certain amount.
Of course there’s no physical barrier in asking, but I suspect keeping certain things on the table will tint what people have come to expect from Monzo.