If Ragnir's size would not be as big, his tanking capabilities and his elemental attacks as great- maybe.
If not for all of that, it basically ends up like Harals fighting Shanks and Gaban, where he cannot him them, while he gets sliced up.
But Loki just has it all. The impact of his lightning or ice powered up Ragnir swings seems to have massive AoE, hence he really does not seem to have any disadvantage whatsoever.
Should be noted that Imu is one of the fastest, one of the most skilled and prolly the most powerful being in the verse, so even if Imu dodges or blocks stuff, it's barely transferable onto anyone else imo.