I have a modified suggestion that I have posted before and I think would work better.
Make the raids simmable similar to put but then have them allowed for each guild member to beat individually.
If you don't want to play it you wait the two days and take the reward for joining (probably around 10th place rewards). But for those that want to do more offer better rewards for each 10% of the raid cleared by your roster alone finally maxing out if you solo the raid. And once you have 50 solos or so you have an individual sim button so you don't have to play boring content you have mastered.
I think thos addresses everyone's concerns. Those that want to play it can and have time to do so (2 days to do it at your leisure). Those that don't want to can still take lesser rewards and don't have to. If you're just joining and not doing damage 10th place rewards are still pretty generous. Those that can already solo the raid can still get top rewards and don't have to try and cramp a solo into an hour a day and can eventually sim it because it eventually gets boring.
And I think the dev time on this wouldn't be all that much. They just have to code it where only your damage counts if this is selected and add some additional rewards. Not a lot of work there when compared to a new mode. And it's more of a qol than new content.
And the part cg cares about, what's in it for them. Well, if you now have a goal to use your roster only to try and solo hstr, then many who are competitive in their guild but only have a couple raid teams that they have time to run would have incentive to go for a solo team or teams to beat other phases. And some would spend to do so.
