Congrats on the bike. Very well specced for the money. The only change I would make is an aggressor or a dissector for a rear tire. The DHRII is a very slow rolling tire. You can save it for when you hit a park day and want maximum downhill traction. Make sure the tires are tubeless as well.
Get a good set of flat pedals (ie. one up), and a proper set of mtb shoes (ie. 5 10). These make a massive difference. I also personally buy high end helmets for whatever extra safety I might get in the case of a massive wipe out, but that’s just me.
Think about how you’re going to hydrate. Personally, I would buy as big of a water bottle as you can fit in the frame (600ml+), so I don’t have to wear a backpack. I rock a 1L EvoC hip pouch and its perfect for a few tools/tube/beer.
Spend a couple of hundred bucks, get a proper bike stand, a proper torque wrench and a few other specific tools and learn to use them. Buy some bike grease, degreaser, carbon compound, Loctite, fork lube etc. There’s nothing like the feeling of a freshly built up bike, torqued to spec, with every bolt properly greased or loctited.
In the summer, you will not be able to get a service booking for almost a month out, you break something you need to fix it yourself. The service you get in most bike shops has also gone way down since the whole covid thing. Everyone is trying to get bikes out the door as fast as possible and things are constantly overlooked.
Last but not least, book a vacation in Whistler. Nothing like it.