If you really think that we are about to see a bear market that will last several years then i think it would be the best for you to don't do anything at all for a few years and once you think that the coins have reached their lowest points you can invest in them. I think bear markets are a opportunity to buy into projects that are already big and established like Ethereum, Solana, Polkadot, Cosmos etc. I would not buy into that coins during a bull market but after a long bear you can maybe get them for a good price. That being said, i don't really think that we are in for a year long bear market or so. Just because it happened back in 2018 does not mean that it will automatically happen again.