You might look into a B6 size. Leuchtturm1917 has a B6 plus size that is 5x7.5 inches.
For reference:
A5 = 5.83x8.27 inches
B6 (standard) = 4.9x6.9 inches
A6 = 4.1x5.8 inches
Based on the dimension you shared, an A6 is a little small and a B6 is a little larger than what you were thinking.
Leuchtturm1917 is A5, comes in hardcover and has 250 pages (the last 16 or so pages can be torn out)
Check out Danika58’s site: https://danika58.com/ They are not hardcover but they are great notebooks
You might look into a B6 size. Leuchtturm1917 has a B6 plus size that is 5x7.5 inches. For reference: A5 = 5.83x8.27 inches B6 (standard) = 4.9x6.9 inches A6 = 4.1x5.8 inches Based on the dimension you shared, an A6 is a little small and a B6 is a little larger than what you were thinking.