I have the following code and when I click the button it doesn't seem to execute the code but once hovered over it will execute the code printing "Hovered!"
 

@SubscribeEvent
    public static void openInventoryGui(ScreenEvent e) {
        Minecraft minecraft = Minecraft.getInstance();
        if (minecraft.screen != null) {
            Screen current = e.getScreen();
            if (current.passEvents) {
                int pX = (minecraft.getWindow().getGuiScaledWidth() / 2) + 88;
                int pY = (minecraft.getWindow().getGuiScaledHeight() / 2) + 60;
                Button button = new Button(pX, pY, 25, 20, Component.literal(">"),
                        (b) -> EasyEffectDisplayMod.LOGGER.info("CLICKED!"),
                        (pButton, pPoseStack, pMouseX, pMouseY) -> EasyEffectDisplayMod.LOGGER.info("Hover!"));
                e.getScreen().renderables.clear();
                e.getScreen().renderables.add(button);
            }
        }
    }

 

You are replacing the button on every screen event (including mouse clicked).

There are many subclasses for specific events, you probably want ScreenEvent.Init.Post which fires after the initialisation of the screen.

Also you can get the screen using event.getScreen()