I am not sure why you insist on describing the concept of existence as "unproblematic", given how much debate it generates. Your conclusion that "The incoherence of sensationalism and of actual infinities argues for a metaphysics upholding the primacy of common-sense existence." does not follow from your premises and does not provide a useful starting point for discussing any concept based on "existence". Do you have an issue with the definition of existence (of something) as that something being an element of reality as defined, for example, by Eliezer in The Useful Idea of Truth:

I need different names for the thingies that determine my experimental predictions and the thingy that determines my experimental results. I call the former thingies 'beliefs', and the latter thingy 'reality'.

If you do, what is it? If you don't, why not adopt it?