Apple iPad Air 11-inch will not connect to Wi-Fi or keeps disconnecting

The checks in more detail

The 6 GHz band has shorter range, so the iPad switches to 5 GHz in another room and may drop briefly. The iPad's Private Wi-Fi Address can be refused by a router that filters devices; turn it off for that network in the network's info. Check for a Privacy Warning or Weak Security notice under the network name. Update iPadOS and the router's firmware. Reset Network Settings clears saved networks. If the iPad finds no networks, a restart usually brings them back, and a persistent failure needs Apple. If speeds are slow rather than dropping, run a speed test in the same spot with the iPad and with an iPhone, and compare:

if the iPhone is much faster, the iPad may be on a slower band or have a stale configuration, and a reset of network settings helps. If both are slow, the router or plan is the cause. Take the test at a few places in the house to map where the signal falls and where a mesh node would help. Check also whether your iPad is using a Private Wi-Fi Address on a work or school network, since those networks sometimes require registered devices and block random addresses. Turning off the private address for that network and asking IT to register the iPad's real address resolves a connection that never completes.

On an iPad that moves from room to room, the Wi-Fi may hang on the first router it joined, and iPadOS does not always roam to a closer access point; turning Wi-Fi off and on at the new location reconnects to the nearest. In a house with a mesh system, band steering can leave the iPad on a slow node, and giving each node and band its own name, or placing the iPad near the strongest node, helps. Record the speed at a few spots with a free speed-test app to see where the signal falls.