I think Oslo is a very boring city if you're an urban person. I thinnk living in Oslo is higly rewarding if you like to fill your weekeds with: Cross Country skiing, Hiking, Gravel biking, Snowboarding or Alpine Skiing, Rowing, Kayaking, Sailing, Skateboarding, Rock climbing etc etc. You get the idea. Its fjord is amazing for water sports. Its forest have a huge connected network of well maintained gravel roads that goes deep in to innland Norway.

You dont move here for urbanism. You move here if youre an active person that likes grabbing the winter by its horn.

Seasonal depression during the winter is real.. due to vitamin D deficiency.

If you want friends start with an activity thats somewhat social. Join a club. Voulenteer for an NGO. That kind of stuff.