The problem with Ibus is that input switching doesn’t work under Electron apps and Chromium browsers running native Wayland (yet, IIRC it might change in the fairly near future but who knows), so you can only type using the Latin alphabet despite having the input mode set to Kana. To me it doesn’t really matter because I mainly use Firefox and can copy-paste non-Latin into Discord, for example, but it might be a major inconvenience for you. This is where Fcitx5 is advantageous, as it actually works with Electron/Chromium on native Wayland:
For the shortcuts, well, you’ll have to look for Mozc settings first, then configure the IME shortcuts yourself. This is how it looks like when accessed from GNOME Settings → Keyboard → Japanese (Mozc) → Preferences:
I ended up mapping the special keys as layers for Home/End/PgDn/PgUp on my keyboard to not mess so much with the default Mozc keys, but it’s still way less convenient than Anthy that has the on_off and circle_kana_mode, which is why I prefer Anthy to Mozc (still have it installed for testing purposes).
At the end of the day the choice of Ibus+Anthy or Fcitx5+Mozc depends if you value convenience or need to type Japanese in Wayland Electron/Chromium. Plus I’m pretty sure fcitx5-anthy is a thing on Fedora repos, so if you want full Wayland compatibility and convenience you might want to try layering it and see how it works (only if it’s not already installed by default, of course).