I recently installed the 3U fan panel in the window seat. It’s powered via a Kasa smart plug, so I can turn it on/off via HomeKit (usually using Siri). It’s quiet, but does a nice job. However, it came with ball bearing fans which I know will get loud over time. I’ll replace them with Noctua fans when they get loud enough to be annoying.
I also built and installed a wide wood drawer on 100 lb. drawer slides. I’m using it to store office miscellany. It has built-in finger-jointed dividers, but I also added some bamboo organizers from The Container Store.
I still need to order a cushion from rofielty.com. In the meantime I’m working on end tables to butt against the window seat.