The approach I’m taking is a blockchain agnostic one. There’s lots of middleware projects with tokens such as GRT, REN and LINK. I see middleware growing really as it has utility in defi but also other applications.
For the past 5 years and the foreseeable short-to midterm. that mainly means ETH (Ethereum), preferably hedged by smaller positions in one or a handful of similarly scoped projects that could end up eating its mind- and marketshare (I won’t judge which are better bets but some candidates would be Polkadot, Cardano, Solana, Tezos. Stay away from EOS and Ripple, there’s nothing behind their curtains)
Other more specific projects mentioned here like LINK, REN, various defi-specific solutions like AAVE/Uniswap, are more perennial and more suited for someone who actually uses these protocols or services, not something I would see as an investment.
You might get yourself some BTC (as a reserve asset for defi), some ETH (as the oil or the machinery which makes the smart contracts go around) and maybe some DOT in case eth2 fails and dot delivers.
p.s. personal opinions, not responsible for losses, etc etc.