Monero without any hesitation! You can always swap to BTC if that will ever make sense for you when you need FIAT.

- You don't want a target on your back or sleep bad at night because you are unsure about who can trace your BTC to you. Way to many people has been social engineered, robbed, kidnapped and killed on that account.

- You don't want someone as the US gov (any government) to come up with a huge tax claim on your perceived balance.

- You want to be the sole decision maker on where and when you decide to pay you tax.

- In this quantum age we move into, you want to hold your asset in what is possible most resistant to that. Monero when FCMP++ is implemented.

- Simply based on market cap. Don't expect BTC to make a 10x within the next 15 years (maybe ever). Monero have the potential to do that within a reasonably time horizon. ROI

I'm not sure about the best wallet option. But, I would probably spread it out on multiple different wallets. And make sure your family can somehow access your funds if you disappear.