I myself am using a TL-WDN4800 with patched hostapd, which will use the blob-free Atheros ath9k driver on Linux. Truly the pinnacle of wifi freedom. Problem in your case is speed, because this card will limit you to ~21 MByte/sec IP throughput. It is 802.11n and that's it. Patch will prevent the 40 MHz channel becoming 20 MHz should neighbors with Wifi also exist. Anything later than 2012 will be ath10k or ath11k (Qualcomm bought Atheros) and the blobs will become a necessity.
To get more speed you will need a card that supports 802.11ac or ax. Like an ALFA Network AWPCIE-AX200. So Intel, with blob. Beware this card has two IPEX4/MHF4 connectors not U.FL like the old cards, so you will need two MHF4 to RP-SMA pigtails which you can then screw into the slot of a "wireless card adapter" like this:
300M DUAL BAND WIRELESS Desktop WIFI WLAN CARD PCI-E 1X Adapter Intel 4965AGN | eBay Make sure it has 2-3 real holes for RP-SMA and does not use PCB mounted RP-SMA solder connectors. Because those usually have U.FL connectors with a small pigtail soldered onto the PCB.
You might need 1-2 meters of good quality cabling to clear the grounded server/PC case and get your antennae into a better spot than right on the back of the case. Lots of RG-XX trash around, anything at 2.4 GHz with loss >> 0.5dB per meter really is not worth it. CFD300 or even CFD400 will do, like this:
Delock Produkte 90464 Delock Antennenkabel RP-SMA Stecker zu RP-SMA Buchse LMR/CFD300 2 m low loss
Finally you will need some antennae. Dual band RP-SMA paddle type dipoles are omnidirectional and cheap, but I wouldn't buy the 2 USD Amazon steal, because those can and will be off-center 100 MHz of the wifi band and you will never know it. So I recommend a reputable brand like Panorama Antennas, e.g. this one:
PWB-24-58 | Dual Band 2.4/5.0GHz WiFi Terminal Paddle Antenna You get what you pay for. If you need more range you will need to go directional, my go-to brand is Poynting. E.g. this one
WLAN-61 - Poynting Tech - Antenna Solutions, South Africa, USA & Europe Of course you could also build one yourself for 3 bucks, see the many videos by Andrew McNeil like this one
And here is a really funny option
Datei:Yagi-Uda antenna for Wi-Fi on Router.jpg – Wikipedia
AsiaRF and mt76 I hear are upcoming options for Wifi freaks once the last ath9k card has died. Also many patches are going into the Linux kernel for different chips of this type. But such a card might be hard to source.
Edit: Probably the wrong "wireless card adapter" because for small cards you need to solder. But you get the idea. Mini PCIe is also not NGFF.