I can't see Swarmkeeper's posts, but I'll definitely quibble with part of their definition of "balance."
"Spotlight balance" is predicated on two assumptions which are generally false in a D&D context:
1. If players get an equal amount of game time (e.g. turns of combat) in the spotlight, then they will get an equal amount of influence on the state of play
2. If the spotlight does in fact point at each player, then they will get about the same amount of game time in it.
#1 is patently false because magic. Magic is incredibly powerful; a single spell, meaning just one turn of combat, can easily do far more than a non-spellcasting character could do in multiple rounds of combat. Hence, some archetypes need only a moment in the spotlight to gain a massive advantage--and thus giving them putatively "equal" spotlight time actually makes things less balanced, no more.
#2 is false because players have significant ability to manipulate how long and how frequently the spotlight points at them. And guess what! Magic both actively and passively keeps the spotlight pointing at spellcasters and away from non-spellcasters or minimal-spellcasters (e.g. Paladins, Rangers, and Eldritch Knights). Actively by way of obviating entire challenges/encounters with just a spell or two, so the non-caster participants...don't really participate. Passively, because spells are so important (especially spell-based healing) that even the non-casters have an incentive to long-rest as soon as the spells are depleted (and the vaunted "time pressure" is utterly implausible to maintain 24/7).
If the two premises above were actually true consistently, spotlight balance would be wonderful. But since they are false an awful lot of the time, spotlight balance is riddled with holes and rarely achieves the claimed results.
This is a huge part of why I am so adamantly opposed to it as a design element. It just...doesn't do what it advertises.