As it's a new noise and not one you'd expect with this engine, IMO there is something going on
Often these nosies are associated with timing chain/or tensioner - faulty exhaust/fittings.
I recall seeing a youtube vlog on some diesel car a few years ago it was a diesel engine and it rattled on acceleration,
IIRC it was something that was associated with the engine valves, springs/ tensioners/adjusters not sure, can't recall but that gave a rattle on harder acceleration.
Start with the simple bits get the car looked at, just tell them what you told us but not what you think it is unless they cn't think of anything and see what they say.