Is spell dmg worth at high levels?

[dmhelp]

Unusually for me, I used PHB initiative rules (IGO-UGO) instead of my normal WEGO rules, in order to keep the results more relatable to other people. For the same reason I also used spell slots instead of spell points, and Legendary Resistance instead of TSR-style magic resistance.

Can you post the entirety of your house rules in this thread or another thread? They sound fascinating.