Yeah, DIYing isn't too expensive when I did it, I think you could do it for around $100 USD for parts, maybe if there are still free sample PCBs available from pcbway or allpcb. That assumes you have a soldering iron and solder and the other tools...
Nice, looks good! Which switches and how are you finding it? I had their low profile optical and it sucked, didn't like the low travel and lack of resistance.
What do you use to change the layout, VIA or QMK? I used ZMK on a Lilly58 and I preferred it to QMK/VIA. I used a nice!nano and the wireless was pretty good.