Does it matter whether surge protectors share an outlet?
It's the amps (or watts, equivalently) that matter

A receptacle can be branched to feed as many devices as you please (within reasonable limits, at least) provided the amperage of the devices stays below the amperage limit of the receptacle/circuit.  For standard North American circuits and receptacles, it's 15A, so if the amp draw of your devices adds up to below 15A (and it darn well should given what you state is plugged in), splitting the receptacle with a splitter tap to feed the two power strips is a nothingburger.

(Yes, there is a small amount of extra risk added by an extra splitter tap plugged in, but practically speaking, if one power strip no longer does the job, a tree structure like what you propose is the way to go vs. daisy-chaining strips.)