Have you tried just putting a few pieces of food on the tray rather than a full plate? I did that and it has largely stopped the throwing!! Still does it if it’s something he doesn’t really fancy - I don’t make a fuss, just put the bits he’s thrown back on the side and offer to feed him one piece so he can taste it. Usually works then he starts eating!
Our son was doing the same sometimes it’s just a sensory / development thing but we also found it was his way of communicating that he was finished with what he was eating. We started with using all done with signs but that wasn’t fully working as he wasn’t finished with everything. So we have got him to say ta and put it in his cup holder or into our hand when he’s done with it and 9/10 meals we’ve not had food thrown. He’s just going on 13 months x it was a process and took lots of repetition .
We went from BLW from 6 months where she would be served a plate and happily pick away at the food and the floor would always be a bit messy as expected. When she started nursery the food all of a sudden would get lobbed everywhere and everything would end up on the floor, it was awful as I felt that all the progress we’d made over 6 months had just gone downhill. She was unsettled from Nursery and had also picked up a few bugs, which didn’t help her appetite. I started instead putting a plate on the table out of her reach and having the different foods on there and she would point and let me know what she’d want so I’d give her one piece at a time and it worked really well. I can now give her more food again but we’re not quite back to where we were h it a huge improvement. Hang on in there, maybe try the option of your little one seeing the food to point at so they have the choice without too much to hand? Good luck xx
Our son did that for about a week or so. We felt the same as you and didn’t want to be too harsh if he wouldn’t understand but we did find that taking away his plate and looking disappointed at him, worked. We would give it back to him after a minute and he would eat properly again.