There are multiple solutions, most rejected by Glitch’s terms, but the better and most effective (and legal) one is buying Glitch PRO and boosting your discord bot.
I’ve read something about making your bot typing forever (actually not the best option), but probably everything else violates Glitch’s T&Cs.
Check these posts (that contain a body similar to this):
@dragonyc1002 There are no solutions, other than paying for Glitch Pro to boost your app, that are not against our Terms of Service and will guarantee to keep your app running 24/7 besides having an app that organically gets enough traffic to keep it awake.
If you can redesign your bot to not always hold state in memory and it’s functionality can be done through application commands (buttons, slash commands, message/user actions), you could setup discord to make http requests to your app which won’t require the app to be 24/7 but glitch handling a application command request from discord when your app is not awake can be problematic