Several years ago, when I was in my 1930's house, I had a very long, galley kitchen. It was solid, good wooden doors and drawer fronts, lots of them all in a dark oak colour. This kitchen always looked dark, just one window above the sink about half way down.
To replace the whole lot would have cost a fortune, looked into replacing doors and drawer fronts, but even that was a good few thousand pounds. Also, I was very reluctant to see those solid wooden doors go to landfill and to replace them with modern flimsy ones.
Solution - I found a company who came down one week, took off all 12 base doors, eight drawer fronts, and seven wall doors, take them away for spraying (Colour of my choice - I chose white), brought them back one week later and it looked like a lovely bright new kitchen. Cost me under a thousand pounds at that time, and when I sold the house about seven years later it was all still beautifully bright and clean.