I haven't changed much on the model. I added a few printable ventilation grilles and installed a few cheaper and simpler parts. I shortened part of the flat bracket to make room for the PVM controller and simply attached it with superglue
I use simple USB-C fan controllers, some of which are available for as little as 8 euros. I also use slightly cheaper filters.
In the end, my configuration only cost about 66 euros + some filament.
(In the picture you can see that I didn't install any flat brakets on the sides because I only realized after printing that I had the wrong screws and could only tighten them when nothing was in the way)
Parts
fans: https://www.amazon.de/-/en/dp/B0BQD467JL?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
Bungees: https://www.amazon.de/-/en/dp/B076H4JMVV?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
Filter: https://www.amazon.de/-/en/dp/B0CDBJVF9G?ref=ppx_yo2ov_dt_b_fed_asin_title
PVM Contoller Amazon: https://www.amazon.de/-/en/dp/B0D3LHYRMH?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1
PVM Contoller ebay (cheaper): https://www.ebay.de/itm/135391427880?chn=ps&_ul=DE&mkevt=1&mkcid=28&google_free_listing_action=view_item
The author remixed this model.
I added printed ventilation grilles and shared which parts I chose differently