BTC and/or ETH for the next cycle?

I'm planning on dcaing a small amount (approximately 20k) over the next 6 months. Currently, I only hold BTC and I'm in two minds about whether or should start buying ETH as well. I've read some compelling arguments as to why it's a great investment, including that it tends to outperform BTC over a bullrun. However, I'm also kind of wondering if it'd be better just to stick with BTC since I'm only investing a small amount. I do understand that diversification is good, but I'm really interested to see what others think on the matter