How can I make members of a Team in Minecraft Invulnerable?

I have a small Java Server on 1.16.1 and use a Vanilla Tweaks datapack ("AFK Display")to have people that stand still for 5+ minutes be considered AFK. This datapack puts them in a team to tell them apart on the Tab list.

I have so far set their nametagVisibility and collisionRule to never, so their nametag cannot be seen and they cannot be pushed around by other players.

Is there a way to prevent these players from taking damage at all? So they cannot even be hit around? Basically making them invulnerable?