OP I felt the same this year. I'm really not a summer person & always put far more effort into my autumn/ winter wardrobe.
Most years I sort of adapt my winter stuff to be summer stuff by adding a lighter colours etc. Last year we were in lockdown & I bought no clothes at all. The previous year I was wearing clothes from the year before so when I looked at what I had this year a lot of it was from pre 2018. And I was SICK of it.
I generally go for quality over quantity so it was all in really good condition & nice enough brands like jigsaw / boden / whistles etc
I did a MASSIVE clear out & I was really ruthless. I divided it into 3 - rubbish for recycling, charity shop & selling. I sold lots of pieces on line & made some unexpected money that way.
Since then I've been steadily replenishing. I concentrated on bottom half first as for me that's thats the hardest to get right. I'm giving up on skinny jeans so I started there.
I've bought 2 pairs of non skinny jeans, a pair of wide legged trousers & 2 jumpsuits.
Then I was able to match tops / blouses & knitwear to match the new shaped jeans.
Next I'm looking for sandals / trainers & a jacket. Perhaps also a couple of lovely sweatshirts to throw on with jeans on a Saturday etc
I've ordered 1 fancy dress for 'going out but hasn't arrived yet
I've watched out for flash sales & codes etc & I've shopped from whistles, sezane, jigsaw.
I usually try to buy outfits rather than random individual items so I know they'll work together etc (learnt this lesson)
I made a list & have worked my way down it. I expect this summer wardrobe to be a base over at least the next year or two just adding more fashionable things as I go.
It's been so liberating & exciting to build up a new capsule wardrobe of new things that I love. My actual wardrobe was virtually empty & that was a bit weird to see but now I love looking in it!