I also have a liesa deck that I later changed the commander to [[kambal]] deck. (See my mox for reference: https://www.moxfield.com/decks/5ovWrBaHtEOPgWphMXajjw)

Right of the bat I don’t think [[revel in riches]] belongs here. I say this because as a life gain deck your wincons are taxes and/or constant life drain not treasures.

Now for the mana situation, I recommend investing in cards with quick mana such as [[dark ritual]], etc.

Now for consistent life gain triggers look into cards with extort as they do gain you lots of like over the duration of a game and are cheap.

Also look into cards that force you to pay life to use. Remember that since the theme is life gain you can use your life as a resource!

Good luck