Since we're now looking at the supposed originators of chakra, i suppose it will be explained soon
Don't think Boruto will stretch that far back. If I recall correctly, Boruto is only commissioned to do certain amount of chapters (like 100?). If that is true, then we are already at the half-way mark. This means that we have 4 more years left and we only ever seen Isshiki's debut.
Considering the main story consists of Kawaki and Boruto, I think Isshiki's won't take up just 10 chapters but more. Then it would need to build to the Kawaki vs Boruto. That period is the only time I think they can even shove in any background info.
Everything else would have to focus on the ninja world collapsing. Kawaki's and Boruto's rise to power. Covering as to why Mitsuki and Sarada might be missing and why it is a 1v1 at the start of the manga.
50 more chapters from this point on is not gonna be a lot. Maybe 150 chapters? so 8 more years? But I doubt they can keep Boruto going considering they are not brave enough to even make full use of Sasuke and Naruto. Hell, they are using them now but they really cannot do anything that will make them standout greater than the newest gen.