The best way I believe to invest your BTC would be to think of a way to encourage more use of BTC
For example;
Split you BTC in to 2 groups, one to invest and another to mature, the amounts are up to you but you may set it 20/80
If you had a coffee shop and every coffee you sold came with a small BTC cashback to the customer's mobile wallet or whatever (some customers are going to turn down the offer so you keep their cashback).
As well as accepting fiat obviously accept BTC as well. over time the returning customers will gain enough cashback to buy a coffee outright, or discount at least, if they do not usually deal with BTC in any other way, alternatively they could use it with other BTC friendly vendors. Also in the meantime some BTC holders may want to actually spend some of their BTC in your shop instead of just sitting on it waiting for something to happen.
It works as a basic loyalty system but over time more vendors of products and services are going to accept BTC, more buy volume on exchanges means prices go up to meet demand.
the BTC price may settle at an amount that you might want to sell your long term stash at or that same stash may become totally useable and with the inflation of BTC value you could buy a new house with it(maybe not?)
More use = more value! (-in fiat, in the short term)
BTC gains value by usage, it is not an asset at all, it is a way of trading value securely without centralised banks
Where it looks like an asset is, in the early years of the transition from fiat to BTC, going to show up the ones who sat on their coins and sold them for fiat
But if the whole world accepted BTC what are you going to sell it for?
As it becomes accepted down supply roots i.e. ; coffee shop owner sells you cups of coffee for BTC because they can buy beans for BTC because the bean farmers can buy fertiliser and tools and pay workers in BTC and the workers can buy food and pay rent with BTC. I'm missing out a few steps but you get the idea.
With any luck in some years we may be able to leave this fiat shite way behind us...