Wifi will connect to the phone but doesn't connect to the apps

The Wifi will connect to my iPhone perfectly but whenever I go onto an app like Snapchat for example. The connection becomes super slow and it takes forever to receive or send messages. Same thing with Discord, Facebook, Youtube, ETC... Nothing works with my phone. I tried rebooting my phone in hopes that it's just my phone being dumb. But I was still having the same problem. I tried another device such as my laptop and that was running fine. I even asked other people in my house to try out the Wifi on their phones and they were fine too! I then decided to reset the network settings in hopes that would help, but once again that didn't work either. I was still having issues even after connecting to the wifi again. I even tried the Airplane mode trick to get a better cell tower and that worked but we're talking about T-mobile, one of the slowest services out there and that didn't help either. I don't know what's wrong with my phone and at this point, I'm ready to figure out if the phone has a problem with the wifi antenna inside the phone since usually I would be all set and ready to go, but nothing is working. If anyone else has any other suggestions I should try. Please let me know, otherwise my phone is completely useless. Oh and before anyone says that the wifi service might be out, I checked that too and it says that there's no outages in my neighborhood.