I'm doing similar in part of my garden, also a beginner.
First, I'm looking at flowering shrubs; they won't die back in winter, so they give structure to the garden in winter, as well as hiding places and possibly berries for wildlife. There are shrubs with great autumn colour or fragrance as well; if those things are important to you, it can really narrow down the list of possibilities, which is handy!
Then I'll fill in around them with perennials, which come back every year. There are loads of fabulous pollinator friendly flowers in this category, and if you don't clear them away when they die back in winter, but rather leave the dead parts there till spring, that's better for birds and insects, who can eat the seeds or nest in the stems, respectively.
You can play around with annuals if you want but try and use self-seeding ones if you're as lazy as I am
Though a load of nice sunflowers along the back would be great, both for bees and birds. They're not hard to grow from seed, and if you save seed from the flower you like best, you can plant those the following year. Sweet peas are great as well, a doddle to grow and very fragrant and pretty and bees love them, and you can just grow them up one of your boundaries, so they won't really take up space.
I know you say you're not interested in growing veg, but how about some fruit canes? Raspberry or currant bushes would be good for pollinators and for you. Or a strawberry patch - it's immensely satisfying growing your own.
If you have a cat, grow some catnip - bees love it even more than cats do, mine is always buzzing.
You want to think of when things are in bloom, as well. There's not a lot around in winter or early spring for pollinators, so you could try and fill that gap for them.
A shallow water source is also useful, in times of drought, with some stones in it for the insects to stand on while they drink.