A few things to point out. First off, it’s your first time using it. It gets easier. I sold loads of 1×10 bikes to guys in their 40s and they all hated it first time out, wanted to put a triple on, get expander rings etc. I told them to stick with it and drop a ring size – now all converts.
You are using a bit more strength than you’re used to, so in the same way as going to the gym after a few years absence is painful and difficult, it quickly gets easier.
Try a 32t or 34t chainring. It’ll most likely sort things out for you, don’t worry about spinning out as you’ll be nudging 30mph when you do. If you do a really large amount of riding up very steep, lose muddy or grassy banks then you just might need an expander ring.