Does this exist? A5, Tomoe River/Sanzen/Stalogy/Kinbor type paper, 5mm grid, 400 pages?

Oof, I've been browsing the internet for ages looking for a nice planner. Some hard/soft requirements that are really hard to find.

• A5
• White paper -- Tomoe River/Sanzen Tomoe, or whatever Stalogy or Kinbor use, the thin 52 or 68 gsm paper with the crinkle, ghosting but no bleeding with fountain pens.
• 5mm grid (preferably a tad darker than Stalogy, I'm getting old)
• opens flat
• has at least 1 page a day, preferably more. 400 ish pages would be great.
• "always in stock" because man is everything always sold out!

What I've found/tried.

• Hobonichi notebooks. Grid too small and the paper curls up in the corners really fast.
• Stalogy - great paper, and my current go to, but the grid is a bit too small and a bit too light.
• LiveNotes , not enough pages, only comes ins 7mm lined.
• Odyssey, 68gsm, 5mm but dot grid and a bit on the pricey side.
• Paper Penguin Co , does not lay flat I think because it's just folded double, also 80 sheets max
• GoodInkPressions, my other go to, I love their notebooks, love their grid and paper, but also doesn't open completely flat due to the stapled binding, and I'd love more pages.
• Sterling Ink notebook - the grid is 3.7mm or something like that, a bit too small, enough pages though so I might try it?
• Pebble Stationary Co - 5mm dot grid
• Sakae Technical Paper Sanzen Tomoe River Notebook A5 Grid , only 80 pages

What I've not tried

• Find a Chinese/Japanese factory and create my own, limited order quantity 100: buy stock for life..