True, however energy produced thanks to renewables already costs way less than its nuclear counterpart (and the gap is growing), offering a way to recoup investments (grid, storage...). Bonus: no risk of major accident, no fuel (uranium), no nuclear waster... https://www.lazard.com/perspective/lcoe2020

Batteries aren't the sole way to store energy. Dams (potential energy), for example, are another one (already exploited and quite powerful and flexible). There are many other ways: https://en.wikipedia.org/wiki/Energy_storage#Methods

"work on all in parallel" <=> (often massive) investments aiming at designing something isn't recouped as efficiently as possible (less units built). "work on a single one" <=> bumping the probability of failure (all eggs in the same basket) There is a middle ground to find!

"invest in the grid" is of paramount importance. Europe: https://en.wikipedia.org/wiki/Synchronous_grid_of_Continenta... https://en.wikipedia.org/wiki/European_super_grid

"connect over larger distances": indeed, and ways to do it are quickly progressing, as do relevant projects: https://en.wikipedia.org/wiki/List_of_HVDC_projects