It's understandable and normal to worry that you're not giving your kids enough, and to play the comparison game, but don't let those feelings fool you into thinking there's any truth there.
I grew up in a very scruffy house. It was being gradually worked on for pretty much my entire childhood, because it was in an awful state when my parents bought it. It didn't have carpets or proper flooring, nor wallpaper or paint on the walls, for a big chunk of my childhood. The garden was largely concrete, in a sort of small square shape. We didn't have a car and walked or bussed everywhere. Holidays were UK based and traveled to and from by train, often with many connections and lots of walking. Accommodation was small self catering flats or Travel Lodge type places.
In contrast, I had a friend who lived in a very affluent area nearby, with a large house, big garden, two big family cars, frequent holidays abroad including skiing, all the expensive residential school trips, kitchen and fridge full to bursting, etc.
I can honestly tell you that I was the happier of us. My childhood felt so full of freedom, imagination and love. I look back on it with such fondness and nostalgia. When I went to friends' houses and played with their endless toys in big bedrooms and gardens, yes, it was fun. It was the fun of going somewhere different and joining in with their lifestyle for a bit - that's all. My friend with the big house and garden had a pretty mixed childhood: both her parents drank copiously and were usually passed out from multiple bottles of wine by the early evening. She was definitely happy in some ways.
But my point is, our childhoods were not defined by the size of the house we grew up in, nor the cars, nor the holidays. It was how home-life was. How free we felt to play and be creative. How loved and secure we felt. I genuinely believe I had the better childhood despite having the "worse" house, no car, no holidays abroad, charity shop toys, etc. So please try and focus on these things, instead of worrying about house and garden sizes. You really can still give your kids a magical childhood.