The "up to 10 apps" of the Nano S will be the same as the "up to 100 apps" of the Nano X - if you install the "correct" apps. Install bitcoin and all its forks and clones and you'll be able to fit on loads of apps because they all use the same base code. Install apps from totally different coins such as bitcoin, ethereum, and monero, and you will rapidly run out of space.

There doesn't seem to be a definitive answer yet to how many apps from different (rather than derivative) coins it can hold at once. This post on reddit seems to suggest you can install at least the 20 most common coin apps, which would presumably include BTC, ETH, XRP, XMR, XLM, BNB, ADA (none of which share their base code) and a bunch of others.

This. There aren't even 5 good altcoins worth buying, let alone 50 or 100. Who needs this much storage space? And who is transferring 20 different coins in and out of their Ledger every day that makes the 20 seconds it takes to install a different app such a huge deal?