Find out when to swap ETH -> BTC ?

The swap from ETH to BTC and hodling BTC long-term is the strategy.

What would be a good tool to find the perfect timing for this?

Is there anything better than looking at this chart?

https://www.coingecko.com/en/coins/bitcoin/eth

https://de.tradingview.com/symbols/ETHBTC/

My consideration:

BTC is the only sensible asset to hodl.

No altcoin is suitable for long-term hodling. ETH is the most interesting altcoin. Other alts do not fit my strategy, as I am not a day trader.

I have had good timing for the swap so far, mostly due to luck.

Fiat does not interest me.

Now I would like to know the name of an indicator or oscillator please