Take a look at some conservative designed portfolios, eg. the Ivy Portfolio, the Allweather portfolio, cockroach, etc.

Many are designed to have smaller swings up/down. While they may miss booms and spikes, they draw down less during volatile markets and downturns.

I dont use it but many on internet (and coworkers) use M1 - you can just set a target ratio and the service will auto rebalance for you.