That's awesome knowing Butler has the higher file size potential as I didn't even know it did. I have had a pair of absolutely massive asset packs which were in the 1.2 gb range and mainly that's due to the high res video VFX elements.
But I had little difficulty just splitting up that material into a list of a few downloads under a single payment.
Maybe some devs with really ambitious PC game work can consider splitting the game project into multiple files / packages as well with clear install instructions for how to assemble them in a single folder so it all works. Not an ideal solution but it is another possible workaround.