I’m currently using a Farad Super 3 power supply for my Pink Faun transport card in my PC. It is absolutely excellent (just make sure you get the 19V option for NUC). Current price is around $650 USD (538 Euro). Shipping to US is included in this price and uses FedEx that is very fast!
https://faradpowersupplies.com/shop/en/home/51-22967-super3-power-supply.html#/dc_output-5v/dc_conne...
Teddy Pardo has one that is cheaper at $450 and also said to be very good:
https://www.teddypardo.com/powersupplies/generic/teddy19-3.html
If your budget is really low, then one of the Teradak on ebay is your only option:
https://www.ebay.com/itm/293045314079?hash=item443adca21f:g:SacAAOSwSRJcsADz
The Teradak is still going to be better than your cheap wal-wart stock power supply, but they are not as good as Farad / Teddy Pardo. I have used Teradak in the past for stuff like NUC or Tivo and they have definitely made a huge difference.
https://faradpowersupplies.com/shop/en/home/51-22967-super3-power-supply.html#/dc_output-5v/dc_conne...
Teddy Pardo has one that is cheaper at $450 and also said to be very good:
https://www.teddypardo.com/powersupplies/generic/teddy19-3.html
If your budget is really low, then one of the Teradak on ebay is your only option:
https://www.ebay.com/itm/293045314079?hash=item443adca21f:g:SacAAOSwSRJcsADz
The Teradak is still going to be better than your cheap wal-wart stock power supply, but they are not as good as Farad / Teddy Pardo. I have used Teradak in the past for stuff like NUC or Tivo and they have definitely made a huge difference.