I think first work on some closed storage I cannot imagine my office in a playroom with kids and how curious they are . As for hardware look at kichen cabinet hardware maybe in stainless not much info as to your style for sure .

Oh this would be when they are in childcare

Emtek and Top Knobs have some nice, simple knobs.

Emtek 86322 Cadet 1-1/4 Inch Mushroom Cabinet Knob - Polished Chrome · More Info

Emtek 86152 Globe 1-1/8 Inch Round Cabinet Knob - Polished Nickel · More Info

Top Knobs - Essex Knob 1 3/16" - Brushed Satin Nickel · More Info

Nice!!! Thank you

Home Depot has great modern knobs of nice quality. Usually you can get the most popular ones in a set of 8.

Thank you!!

I love your polka dot carpet! For a more modern look, why not try simple black knobs. I could see you going with more black desk accessories, graphic art, etc. You have lots of other colors in your space, given the toys and children’s books. But your space can lean modern, sophisticated, too.