Horey Shet, I did not expect such detailed and in-depth discussions since my question was quite stupid and short, hahaha.

I'm quite lucky as my Fire has the best weapon grid and the largest hime pool of all my elements. 8 SSRs, 12 SRs, and 11 Rs with Balance/Defense/Tricky covered. So I guess just pump my grid a bit more while leveling them all up so I can customize team better.

Also about Keyen's advice, I think that is a bit situational? If we used the upcoming tower as an example, we happen to have a Fire UE right before it with a Pride and an Assault SSR. If the grid contains only 3 SRs waiting to be swapped out, we could argue that after replacing 2 SRs with SSRs, the remaining SR probably should not be leveled past 8. Reason being that ONE SR won't be there long enough to make the investment worth it for 6% assault. But if the grid has a bit more SRs(4+), then it would be worth doing so because those SRs would have a longer life-span on the grid.

But I guess even then, no matter the situation we can say that one thing probably holds true, and that is IF the soul weapon in question is Solomon's then it might be better to just leave the weapon at SL1. Solomon would mainly be used for floors 1-8, and to my understanding she benefits more from Char ATK(assault/eido) than "Element" ATK.

There is one thing about Keyen's math which I am very confused about, mainly because I actually don't know the formula. The extra 45% elemental attack used, probably comes from elemental advantage... but I thought the bonus from elemental advantage is multiplicative to everything and not additive to Ele ATK.