When you checked the oil was the motor hot or cold? If it was hot I'd add some because hot oil expands and will read higher on the dipstick when hot. Personally, I like to check the oil on stone cold motor that has been sitting overnight. I do this for a few reasons. Aside from the fact the owners manual says to do it that way; cold oil tends to cling better to the dipstick making it easier to get a good reading. Subaru dipsticks are notorious for being hard to read in my experience. Another reason is cold oil density is higher so it will read lower than when it's hot. A number of Subaru's I've owned had a notch in the dipstick a little bit above the high level mark to show how high the oil could be when hot. I'm not sure when they removed that but my kids Forester 2001 has it (see attached) but my wife's 2013 OB does not. Maybe it's a 2.5 VS 2.0 thing I'm not sure but two of my H6 motors had it as well. In short check it again when the motor has been sitting over night if you checked when it was warm, just to get a more accurate reading. If it's between the dots you are technically okay, myself, I'd add oil but that is more to make me feel better than anything else.
The oil I use is Mobile 1 this stuff here
Mobil 1™ 0W-20 Advanced Fuel Economy | Mobil™ Motor Oils
I use this filter since I always change my own oil: WIX 57055XP:
Part Details
Every new NA motor Subaru I've owned, I do the first oil change at 1K miles (1.6K km), 3K miles (4.8K km) then 5K (8K km) and then stick to 5K intervals. It's just the way I like to do it, feel free to say "okay boomer", If the shoe fits

Cars use to come with break in oil but not anymore.
Also when it comes to the oil light AKA "idiot light", there are two different types on our car. Subaru's now have a oil pressure and level sensors. So the light coming on looks similar but there is a slight difference in look but a big difference and how it can effect your motor. See attached.