Strange choice as it's a poor league and isn't going to prepare him for the physicality of the PL which is his only obstacle imo.
Playing week in and week out is certainly a good thing but adapting to the physical nature of the PL, especially with the new lenient refereeing, is also an issue, several players have found that over the years.
I don't get this notion that 19 year olds get stronger by being pushed around by stronger players.
It's mostly time in the gym + time that develops them physically, it's basic physiology. Reminds me of the silly practice of of American Football training without water.
Most PL players from the Eredivisie have said that the high tempo was the thing they struggled with most, not physicality.
The upside to this loan is that he's guaranteed to start and Feyenoord are playing twice a week (cup and conference league). PL teams probably couldn't make promises regarding minutes and the quality of play is better than the Championship. Their manager is playing good attacking football with a lot of pressing. He'll play in a packed stadium with quite some pressure to win.
I'd have rather seen him go to a better league, but it's not an odd choice considering most of our kids end up on the bench in Serie A/Bundesliga. The deal reminds me of Odegaard to Heerenveen.