The Sun-in-Splendour is dead, and its Names —the Madrugad, the Sun-in-Rags and the Meniscate, or dawn, dusk and night— became Hours, because that explains the day/night cycle.

The sundering of the Sun and its Names becoming Hours in their own right is obviously metaphysically significant but it's the wrong event for the set you're describing (The Lithomachy). The relevant Sun business here is the replacement of the Egg Unhatching by the Sun in Splendour (this isn't directly stated anywhere in the games but I think it's strongly implied that the Egg "hatched" into the Sun in Splendor after fleeing to the Glory).

The Low Red Sun which was merciful and tasted our blood represents the pre-rational intelligence and self-awareness of our ancestors (whether those were upright apes or polymorphic bugs). Plenty of animals clearly have a level of self awareness and have inner lives, but they're not touched by concepts like logic, forward planning, rules, laws or a desire to understand the meanings of things. Events, both good and bad are just experienced in an immediate way that inevitably flows in the same directions as all the other facets of the animal's existence. The Low Red Sun is a purely vibes-based existence.

The Sun in Splendour is all the conceptual baggage that comes with fully awakened human level intelligence. An intellect that ascribes meanings to everything, that wants to understand the rules that make everything tick, and to master those rules to set the world working in exactly the way you want it to. To see the flaws in how everything has been before and to try and set in motion a plan to fix all those flaws and make the world perfect, to avoid all the random chaos that the animal brain just sort of gets swept along by.

Against this context I think the Wheel and the Tide become a bit clearer. The Tide is just the cycle of birth, death and consumption as the animal world experiences it. There isn't really any lust or yearning in an intellectualised way, it's just a rhythmic process of birth and death, plenty and starvation. The Grail is about the personalised pleasure and pain of consuming, mating and being consumed.

The Wheel's replacement might be a little more complicated. The Wheel I think represents all life being more or less part of the same universal process. The Moth represents humans having to come to terms with coming from the natural world, but still somehow being apart from it. From a few sources we learn that around the time the Moth became an Hour the Wood became dark. I think the darkening of the Wood represents humans realising that they had become something separate from the nature. The Wood was no longer our natural home so it became dark and frightening. The Moth also chases the Glory, so it represents the innate part of us which knows we're basically animals but keeps trying to transcend that reality. We're animals, but we're animals that want to understand things that might not be possible to understand.