Russia is around the fifth highest spenders world wide, with a high percentage versus GDP (4.5%) compared to many other nations.
The UK actually don't spend much less in fiscal terms, but it's a lower % of GDP although still above NATO 2% desire/requirement at close to 3%.
Collectively, we far outspend Russia on defence, still there's a lot more to it than that. Lots of NATO countries do not spend 2% with only US, UK and France.
There's also the issue of Russian conscription, how much they spend per solider and the general cost of equipment compared to costs her.
Their standards are increasing although the mantra has often been quantity. It costs us a lot more to train and maintain each solider compared to Russia.
Same with equipment. Still, you're right: we spend far more collectively but the issue is with efficiency and it's spread across maintaining lots of separate forces.