Commander damage punishment

I've been playing magic, with my current play group for a couple years and going to SCG cons and local Friday night magic command nights.

The guy whos house we go to play at, has a house rule that we don't play with the Commander damage mechanic. Because I like to build decks that revolve around commander damage (ie traumatize+ reille the everwise) or (multani + scapeshift) or (yahenni + plague winds).

This has not been a problem until recently. He built the four color omnath Commander deck And it's really good at gaining life. I did 43 Commander damage in one turn (with reille my beloved) but then lost the game. Needless to say I was kind of salty.

I am currently doing the 32 deck challenge and trying to build one edh deck for every color combination. I have decided to build my black white edh as super hard life gain and some light removal and nothing else. I figure that if I can gain an unfathomable amount of life I can't lose (except for combos/alt win conditions). Also I plan to specifically not block commanders with this deck just to be petty

I'm doing this in hopes to punish the group for not using commander damage. However my questions are 1.) are there any other ways to punish people who don't use commander damage and 2.) can you think of any black and or white cards that could gain an absurd amount of life

Side notes: This is a friend I've had for 8 plus years and know really well outside of MTG so I can't just not be friends with him.

Also I'm running immortality beacon, famished paladin+ resplendent mentor and Karlov as the commander

Thx for reading mtg homies👍-j2s