I'm glad YOU are happy, and I absolutely understand that you aren't doing this, but a super common thing is that someone mentions a hobby -- pens and notebooks; home espresso; motorcycles -- and is then deluged with instructions about how they should do a bunch of stuff that's really part of the second order hobby (the DIY stuff) and not about the main activity.
I just want to make coffee, or ride my motorcycle, or have good pen and paper options. I don't need to
- Hack a chinese grinder instead of buying a turnkey device; or - Modify a bunch of stuff on my motorcycle when it works just fine as it is; or - Make my own notebooks
But if you're happy doing these things, bully for you!
The notebooks / exercise books the school supplied could hardly be considered expensive, so you may just need to shop around. Or maybe downgrade to use cheap ink on a cheap notebook?
Fountain pens are exclusively hobbyist items. Children are never taught with them, and that kind of penmanship hasn't been a normal part of childhood education in the US at any point in my lifetime.
If everyone is using a ballpoint with paste ink, the paper can get progressively crappier and crappier for a long time before anyone notices.
When I buy notebooks in the UK, though, I find that lower-end notebooks tend to be nicer than their apparent equivalents in the US.
You just have to experiment with some and once you find a lineup supported by a good company, you are set for life.
Mainly, though, I'm replying to push back on the "set for life" aspect of your comment. Paper mills change, and so do notebook makers. Moleskine used to be fine, but they started using cheaper paper a long while ago and my usual combo of Vanishing Point + Pilot cartridge ink started bleeding really badly.
The point is that eventually, someone at $notebook_company is going to change things up, and the odds are that change will make things worse. So you kinda always have to be looking.
The paper in my Barton Fig journal is fine for, say, my Vanishing Point pens with stock Pilot/Namiki ink, but my Aurora with Birmingham Pen ink bleeds intolerably there. (This is one reason pen people tend to have multiple pens inked at once...)
Anyway, at my desk, I'm using currently a Rhodia Goalbook blank journal. It takes anything I throw at it.
If you can find it, Tahmoe River paper is really great for almost any combo, but they recently changed the mill and I understand the new version isn't as great. Finding it is always a bit of a Thing since they don't make journals; you just have to find a company that's making books with their paper.
I used Moleskine for years, but at some point a while back (a LONG while back), their paper changed and my go-to combo (the Vanishing Points + cartridge ink, because for years I flew all the time and this made it easy) stopped working well on that paper. I moved on to Leuchtturm 1917 notebooks, and they were more like the old Moleskines, but I moved off of them when I started using a wider array of pens and inks because while the L. paper was fine for the VP, it didn't handle fancier/wetter pens as well.
L. now also makes a heavier paper variant, and I have one I haven't started using yet, but I hear good things.