I have a 2019 Outback 3.6R
I have a 2019 Outback 3.6R Touring. I have had zero issues, though did have to jump it once because I left the dome light on for three days. But I already had a lithium jumpstarter.
I live in apartments and my car is a distance from my apartment with lots of concrete in between.
That said I am planning for my parking cameras to add a trickle charger and shore power outlet (havent figured out where) which will keep the camera batteries powered and top up the battery when sitting.
I have let my car sit for days at a time without issue as well, longest was about a week without driving it. That said I read stories of people here leaving their cars parked for weeks at a time and not expecting issues. Even older cars with little to no parasitic draw would see battery degradation if the sit that long. If youre not charging the battery regularly, it actually damages the battery and causes it to fail. Battery maintainers help with this if you dont have super regular use. They are also useful to run certain modes to desulfate and equalize the battery. Sulfation is a situation where sulfates form on the lead and inhibit charge and discharge of the batter. Equalization is when one cell is holding less charge than the other cells, and due to how batteries work, that becomes the limiting factor for all the other cells.
Now Subaru does use small batteries for the size of engine. I do plan to replace my battery after next summer (summer 2022) when it will be 3 years since I bought it.