I was checking with the addons that adds text with current/max levels of Health, Magicka and Stamina, and also with the UI source code that handles that as well and found that if you type this
Lua Code:
/script ZO_PlayerAttributeHealth.playerAttributeBarObject:SetTextEnabled(true)
/script ZO_PlayerAttributeHealth.playerAttributeBarObject.forceVisible = true
Your Health bar stays visible and with text. No addon needed.
Is it leftover from a previous implementation or something that might gonna come on a future patch?
Also it doesn't work completely, something else always end up hiding the bar again.