I know for sure I won't be able use SE as my primary as my eyes won't be able to read anything LOL.
Why won't you be able to read anything? The pixel density resolution is the same on the SE as the 6 and 7 (326ppi) and so the text size is the same, in standard view.. it's just the canvas area is larger on the bigger phones. The + phones do have a higher display ppi (401 ppi) which would actually render the text smaller, except for the shadowy world of 3x scaling, and apps being updated properly, so results are less predictable and vary between apps!
There is of course a 'Larger type' facility in the accessibility settings, should you need it. Apps that support Dynamic Type make this even more useful/customisable to your eyesight and preference.