I've not got a Sony phone, so I'm fumbling in the dark here, but here goes anyway . . .
1. If you enable the 'smart backlight control' feature, the screen will stay illuminated as long as you've got the phone in your hand (obviating the need to periodically turn it back on again, by whatever method). It will only turn off when you put the phone down. See page 18:
https://www.sony.com/electronics/support/res/manuals/V171/V1710908M.pdf
2. I've no idea! However the section entitled 'To enable or disable other sounds and tones' on page 55 might be relevant.
3. I've no real idea again! (Sorry!) Is there anything relevant that can be accessed via Settings > System > Date & time?