Looking for some feedback on my Loxodon Mammithicus (DM Homebrew-ish) Barbarian, and some of my character choices.

Hey guys, I don't think I've ever posted here, so hopefully I'm not breaking any rules or anything like that.

I'm looking for some feedback/suggestions, as stated above.

I am thinking way ahead to whether or not I'm going to want to multiclass with this character, as I've never done so before and I'd really like to give it a crack. Currently stewing ideas of Fighters, but looking for some other suggestions to bring the hurt in inventive and dynamic ways!

See below for a breakdown of what I'm working with so far.

We have started at 2nd lvl and our DM has been really generous with homebrewing stuff, giving us powerful items and boosts to ability scores where it makes sense, etc. To elaborate, I'm a 20 Str Barb with resistance to Cold from a racial bonus and Necrotic+ 3 extra AC from a seal I had cast on me because of background reasons, 47 HP because he gave everyone an extra 10, then gave me 15 because I am beeg stronk boi, plus a 1d12/1d20 Magic Greataxe that I can use Versatile because I'm almost 8 Foot, and 350+ lbs, ALL of which was the DMs idea and insistence. while that may sound broken as hell, and that was certainly my concern as well (I don't want to overshadow anyone), he has assured us that he won't be pulling any punches when it comes to enemies, encounters and BBEGs (We're fighting a Gibbering Mouther at lvl 2 WEEEEEEEEEEEE).