Edit: The single best way to change FoV currently is probably with this mod: https://www.nexusmods.com/masseffect3/mods/663? Also works in MP (see mod makers notes for details) and retains the slight FoV changes through different action that the ME3 makers intended, e.g. higher FoV when sprinting.
The old way (that still work in MP) of changing FoV:
Turns out that changing with FoV with set SFXGame.SFXCameraMode FOV 90 instead messes up multiplayer. You can not play MP if you activate this command. You simply get a connection error when trying to create a lobby. Can not confirmed it is the same when joining a party, since nothing happens when just starting a search and it takes quite a while to find a game and I do not want to botter with it ATM. However, it would surprise me greatly if you did not get the same connection error when you find a match and try to join. Neither does the SFXCameraMode FOV command work in multiplayer at all. I suggest using the old method instead if you plan o playing MP: https://www.reddit.com/r/MECoOp/comments/14b1ek/guide_how_to_change_your_fov_pc_only_sorry/?ref=share&ref_source=embed&utm_content=title&utm_medium=post_embed&utm_name=db8d2f54cb6444619d42c17e8a173d13&utm_source=embedly&utm_term=14b1ek
Then to make this work in cut-scenes for single player you instead add: ( Name="F1", Command="FOV 70" ) under the bindings tab of sfxgame.sfxgamemodecinematic and sfxgame.sfxgamemodeconversation instead. Then when there is a cinematic or conversation you press your hotkey. If you do not play MP I guess it is not an issue, but at least I rather press one button the few times there is a cut-scenes in SP then miss out on high FoV in MP or having to restart the game and swith between two Coalesced when playing SP or MP. So no, it does not work perfectly it seems, just like I recall, just that I could not remember in what way it did not exactly.