I think you can improve on the soil. Lots of good discussion here in the forum on soil. Piecing together yourself will give the best results and is most economic.

And the spots look like fungal. Is it spreading? If fungal then I would remove the affected arms - recommended to wear gloves so you don't get irritating sap on your skin. If not fungal then it could be sunburn.

Otherwise looks okay. The base is healthy and solid. I see one leaf coming out so watering isn't too crazy and that confirms there is water getting to it as well.

Thanks, @ewwmayo. I believe it is fungal. After being out of town for a week, there are new spots and they look to be almost like blisters...

It looks like it isn't getting enough light/sun. I grow mine in full sun and it is much more compact. Rot (fungus) is probably your issue.

I have two of these and they seem pretty darn resilient. I'd just remove the branch with the brown fungus type thing, give it a good wash down, and back it up from the sun a bit to avoid sunburn.

I agreee with ewwmayo about the health. When it puts out leaves, it's getting water. They will not put out leaves if roots are bad or they are underwatered.

they can take a lot of sun, but they need to be acclimated. I burned mine last year just from putting it closer to the window.

Thanks Lauren (zone 9a). Maybe it's too close to the window... We went on vacation for a week+ and noticed there are some almost "blister spots" on the trunk now (at the very top).

This is Euphorbia Lactea not trigona.

I agree not trigona, but suspect not lactea either (unless SEVERELY dehydrated one). Can't find an exact match for it.

So how is your Euphorbia doing now?