After updating my iPhone X to iOS 13.4, the home indicator refuses to swipe up again. How can I fix it?

So this is happened before? Since you said, "again".

Try a forced restart, press and release the volume up button then immediately press and release the volume down button, then press and hold the side button until you see the white apple logo then let go of the side button.

But did you try the forced restart? Do you have a case on your iPhone? If yes, try it without the case.

I gave you the instructions in my first reply to you.