"Ideal" isn't doing as much heavy lifting as I thought it would be in this article. This is a basic wardriving setup on flat ground.

Standard wifi is phy limited to ~1600m unless you can increase ack response time limit, otherwise retransmissions will be sent by the sender while ack's are being transmitted by the receiver.

Then, per friis equation, with enough power and antenna gain (it's the antenna gain that really matters) the limit is only obstructions/terrain. Get yourself high enough (mountains, planes, satellites, moons, etc), or bounce of an opportune reflector (planes, moon, aurora, meteors, ionosphere, rain, hail, etc), and there is no real limit, besides how big of an antenna you're willing to build in orbit :P

or just make the throughput really really really REALLY slow and ice your receivers with liquid He.

Hams make a game of it: https://www.arrl.org/files/file/WA50-Standings/Distance-Reco...

For discussion purposes just "WiFi" isn't doing much. I doubt typical AP<->phone 802.11ac on 5GHz can achieve >1km let alone 802.11ax/be on 6Ghz carrier, even 802.11n can only reach a few hundred meters with line-of-sight, sunny day, and no interference

Long range WiFi is a "solved" problem with 802.11ah with sub-Ghz carrier and can reach more than a km depending on bandwidth requirements

All that assuming tx power is within regulation, no enterprise grade antenna, and all with commercially available parts