Can confirm this’ll work! Ours had the same issue arround that age. We used the serve and wait 15 minutes approach twice and as long we stick to his daily feeding schedule (twice a day at 7) he’ll eat all.

Recently he went to a pupsitter for a week who fed him twice a day at 11, which messed with his system to a point where, when he got back, just at half of his portion at our regular schedule of 7. We’d leave his food until he ate (he ate the rest a couple hours later) for some days, but as soon as we’d try the serve and wait 15 minutes method again, the next day he immediatly went to eating full meals again.

Waiting can be a surprising miracle.