I just addressed this problem, but I may have gotten it slightly wrong. I wanted a really warm layer (but decided against fleece because fleece doesn't compact and I'm going to a place where every other occupant is a sheep.... great excuse to buy a sweater.)
My criteria: lightweight, warm, water resistant, packable (so I can have it in my lightweight day bag without looking like I'm smuggling balloons), and while reading the reviews I added: breathable not sweaty.
I found this page of reviews
https://www.switchbacktravel.com/best-synthetic-insulated-jacketsSeemed better than most similar 'best ofs'. I learned a couple of things. 1. synthetic insulation seems to be gaining fast on down (personally can't speak for down, my nose immediately stuffs up, sinus pressure, can't be around it--unless it's still on the goose) 2. Some of these jackets 'breathe'--so they seem to be comfortable in a wide range of temperatures. "Oh you mean like a sweater?" and some the wind seems to blow right through--and costs twice as much.
So off to REI (American for Cotswolds). Ended up ordering a Patagonia Nano-Puff Hoody (different from the Nano-Air, and the Micro-Puff....) Which it turns out one review said 'sweaty' another said 'breathable.' Or I just got it wrong; in the end I don't think it'll be that critical. It stuffs small--most of the jackets on the list do not. And they don't. (The ArcTerx was better as an overall, but it stuffed as willingly as an angry-12 year old.)
One that was high on my list was the RAB Xenon-X, warm, packable, not locally available for me, but it is for you.
In the store I noticed a lot of these jackets
have fabric back panels. Total surprise. None of the photos show anything except the puffy parts. Weird. I don't think they're just cheating on the insulation. I think they figured out people want the puffy look, and fabric panels didn't fit the 'look'. It must be that the lower back is where we generate a lot of heat and sweat, it's covered by the backpack... I figure they know what they're doing. (Fashion? Ha. In a couple of years everything we have will be Cuben/Dyneema and Tyek house wrap, and were all going to crinkle and crunch. 'Great gear, but don't forget your hearing protection....')
I expect the jacket I bought to be toasty warm, trekking and in camp, but with my rain jacket as a shell if it's windy or rainy, also as an option in my sleeping bag (I sleep cold.) In the city it'll be in my day bag.
Hope this helps.