I'm hoping someone else will jump in to help, as I have a Learning model (I assume you have the Nest not Learning not E model) and I have only a heating system. So I can't give a definitive answer. But I will speculate, hopefully not too annoyingly.
One thing it says online, in this article https://support.google.com/googlenest/answer/9247301?hl=en, is, "Note: Heat, Cool, and Heat • Cool modes each have their own temperature schedule. If you want to make changes to the schedule, be sure you select the right one." That makes it seem like you should be able to go into a Mode and then build a temperature schedule from there.
On the other hand, you refer to the Comfort preset, implying that you want to use it in both Heat mode and Cool mode. But you're also implying that your Comfort preset has both heat and cool targets. I wonder whether you want to set up two new custom presets, one at 73 named Winter and one at 74 named Summer. Then in Heat mode your schedule would be based on the Winter preset and in Cool mode your schedule would be based on the Summer preset. (If every preset has to have both heating and cooling targets, you could set Winter to 73 heat / 88 cool and set Summer to 53 heat / 74 cool.)
Again, I don't really know what I'm talking about so I apologize if I'm sending you off on a wild goose chase!
Experts, please have a look!
