Change climate sensors / ranges based on mode or time of day

Starting a new climate automation and I’m having a hard time thinking about where to begin…

My master bedroom gets hotter than the rest of the house, so when we are sleeping we like to have the temperature in the house lower to keep the bedroom cooler… we also sleep with the bedroom door open to allow air flow. Problem is, I like to take impromptu naps at times and we have a cat who likes to be annoying during naps. So, I close the bedroom door if I take a nap, but that can cause the bedroom to get to some really high temps.

I have a Nest thermostat with a built-in schedule that handles most of my day fine, but I’d like to override the Nest schedule to prevent sleeping in sweat… my understanding is I’d have to clear out the Nest schedule and use HA to manage the whole schedule in order to not have any unexpected triggers… am I wrong on this part or is there something akin to a manual/automatic run? (where “manual” would be me controlling it through HA) I don’t think the Nest allows this…

On to my main point of this project, I need to be able to change the sensors that my thermostat is basing its heating/cooling off of on the fly… Basically, I want a “sleep_mode” where HA tells me thermostat to heat/cool based on the bedroom temperature sensors I have, but otherwise heat/cool should be based on the downstairs temperature sensors…

Does anyone have any ideas of where to even begin with this? I can draft up some pseudo-code to be more specific of what I’m trying to do, but I’m having a hard time deciding where I would start with managing the thermostat based on ranges that are set by different groups of sensors at different times…

Why not just throttle the heat supplied to your (overheated) bedroom? No code required.

Forced air system? Constrict the floor vents.
Hot-water system? Close the radiator’s air-vent.

Well… I can close the vents and that helps to an extent… I’m just trying to maintain a balance of not too hot, not too cold… which is a lot harder to do by just playing with vents than adjusting when the thermostat is running… I’ll keep playing with what I’ve got and post something close to what I want if I can figure something out…

This honestly might be a use case for some smart vents… I’ve honestly just never looked too much into them due to the high price point and everything I’ve read says that constricting vents too much in an HVAC system that’s not built for it can lead to a lot of problems.