Bree_425
I'm wondering if your phone is on a different network than the Roku. Many network setups have both a 2.4 GHz and a 5 GHz network connection. Some will not allow devices on one to communicate with devices on the other.
Use your actual Roku remote to see what network your Roku is on. Settings > Network > About
If the channel is above 13, you're on a 5 GHz network. If it's below 14, you're on a 2.4 GHz network.
Then look at your phone. For Android 12 phones, go to Settings > Network & Internet > [your network] > [settings gear] > Frequency.
If it's the same, and your phone app still won't connect, try removing the app from your phone, reboot your phone, then add the app back.