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I've tried waist packs before and I really don't like the feeling of weight on my waist, so unless something has radically changed I think I want a back one. I have a number of Camelbaks - one is functional but heavy and large, the other is smaller but gets rounded when filled and because it's so old the phone pocket is tiny.
The basic Camelback ones seem like what I want but they don't come with a waist strap, which I think is a bit of a pain as the thing hits you in the head on steep stuff. At least, it always did for me.
I need about 2l of water capacity; a phone pocket; a place to put multi-tool, tubeless kit, quick link etc and a tube; and a place to put a mini pump. Maybe somewhere to stash a windproof but I may not bother with that.
I've not tried one myself, but looking for something similar this Decathalon one seems to tick all your boxes
They ain’t cheap, but the Camelbak Chase range is worth a look even if only to confirm you don’t want one.
I have big one and my son had the smaller one. Both are good.
They also fit under a gilet or waterproof which is useless this week but great for keeping mud off them a few weeks ago
This is the larger one.
USWE Outlander?
https://uk.uswe-sports.com/shop/shop-by-type/motosport?activity=7
Its been renamed but I have the old 1.5l version, it never moves and the option of the removable Pouch is great for long distance racing.
I use a Decathlon running hydration vest. Maybe not narrow, but don’t bounce at all and available in a few sizes of storage capacity.
I have a Camelbak Lobo, it is quite narrow and has a waist strap.
It's fine for 3-4 hours, fine for a few bits and pieces, but wouldn't get a jacket in it.
Have a look at the Dakine Session.
I have the Drafter and Nomad and both are comfy & very durable, if not the most flashy.
Not cheap though.
1.5 Chase bike vest best fits your description perfectly
Dakine shuttle is great. 2l bladder. Had mine for a couple of years.
How much d'you want to spend?
Mission Workshop Hauser it's silly money, but indestructible, and fits your requirements.