iPad Wi-Fi connection extremely slow

We have six devices at home: a Samsung mobile, an iPhone 12, an iPhone 15, an iPad 8, an iPad 9, and another iPad 9. Unfortunately, all three iPads have been experiencing extremely low connectivity after updating to version 17.3, and even updating to 17.3.1 didn't solve the issue. We can't even browse the internet, as the speed ranges from 1 to 3 Mbps across all three iPads. Meanwhile, the iPhones and Samsung device have internet speeds ranging from 150 to 190 Mbps.

I've tried every solution I could find online, including updating the iPad software, closing all apps, doing a hard restart, resetting network settings, resetting all settings, restarting the internet router, and even resetting it to factory settings. Unfortunately, none of these solutions have improved the situation.