Hi! I'm kinda new here too

Not a lot of post at the least.
Seeing as the OPamp is (close too) a perfect gain/block, swapping them
should be of no major consequence. Of course there will be
some difference, whether its clearly audible or not would depend on the OPs swapped and the application. I`d try to swap the stock ones for other types of monolithic OPs first, before venturing into constructing your own. There`s both JFET and CMOS low noise/audio OPs commercially available. TL7x/6x/8x are popular JFET types, but cant think of any CMOS right now.