I watched both series, but Monogatari has more characters and the world feels bigger to me at least. While Madoka had potential, it was still a show about two characters and 3~4 secondaries characters that weren't that relevant.
Obviously, MagiReco proves I was wrong. People are interested in more characters and stories using that world and it's concepts. I just felt like Monogatari had more to offer in the mobile space as you have many different kinds of characters with their own arcs and fanbases (Senjougahara fans, Nadeko fans, Shinobu fans) like the Fate franchise.
The lore of Madoka is that there were hundreds if not thousands of magical girls since the beginning of human history, the anime just shows present stuff but from the get go it always had a potential similar to the Fate series (it's also a terrible depiction of women because every important woman in history HAD to be a magical girl according to them <_<)
Since the TV series they also extended the cast of Madoka through other medium.
Monogatari has a few problems, it has a finite cast with characters that got lengthy developped across multiple hundreds pages books, every possible character mentioned has already appeared at this point and they can't just create dozens of random characters for a mobile game like that either considering the format and they can't pick something from other lores (like Fate is doing with legends across the world, I'm not familiar with the extended cast of Magia Records).
It's basically a character driven history whose lore doesn't fit the gacha model and who hasn't been there long enough to produce a big enough cast either
Take Tales of for example whose games are a very character driven, they were able to create gacha mobile games (3 of them even) because it's a 20 years old series with a dozen of main entries and a few spin-off with a total roster surpassing 100 characters.
Monogatari has what? 20-25 characters? That's nowhere near enough.
Fighting is also not a central theme at all, which brings the problem of what gameplay could fit the IP (and probably why they ended up making a puzzle game), you could bruteforce some kind of fighting gameplay regardless, but using a form of gameplay that doesn't fit the IP is more than often a recipe for failure.
So you can't use the characters for gacha, you can't use the gameplay that most gacha games used, what's left then?