Should I use the 5-day MA to manage my ETF positions? Is it this simple? Look at the chart.

I’m transitioning from passive investing to active swing trading and I’m reconsidering what to do with my long-term ETF positions. Look at this chart: https://www.tradingview.com/x/E2NVwsHN/

Looking at ETFs such as VT, a simple rule seems appealing:

Hold or buy when price closes above the 5-day MA
Sell when price closes below it

Visually, it appears to capture many of the uptrends while avoiding part of the declines. But I assume the downside is whipsaws, missed rebounds, taxes, and trading costs.

Has anyone actually tested or used this approach on broad-market ETFs?

Would it make sense to actively manage ETF exposure with the 5-day MA, or is it better to keep ETFs as a passive core and use separate capital for swing trading?