Seed phrase and risk management: multi-sig best option?

I’ve been accumulating Bitcoin for 3.5 years and I’m at a point where I have life changing money that I want to protect. I currently have my seed phrase written in a notebook that’s always on me but I know that comes with risk. I also have a copy of my seed phrase at home but I know there is risk if there is a fire. I’m tired of worrying about fires or losing my seed phrase so I’m researching multi-sig setups. I know Casa and Unchained have multi-sig setups. Has anyone tried Casa or Unchained 2/3 multi-sig set-ups? Is multi-sig worth the money? Any suggestions on how to store my seed phrase? I tried buying a metal plate off Amazon but it didn’t come with a tool so engraving the plate was difficult. I know that saving my seed phrase in my notes App is a bad idea but it is the most convenient option. Having a physical copy of my seed phrase leaves me vulnerable to fires, water damage, theft, and losings it. PO Boxes get robbed where I live so that’s not an option. I don’t trust banks to hold my seed phrase. What other options do I have? It’s been 3.5 years and I still don’t have my seed phrases stored in a way that feels safe for all of the time and energy I’ve got in Bitcoin. I’m looking for suggestions and ideas.