Reminding that ETH was already 5 years makes me feel regretful again for not buying it when it's price was below 50$ even though I have huge stock of BTC that time.

Regretfully so too, not investing in etheruem early enough isn't really a good story. But is a lesson for many like me too to invest in some coins with value now and maybe in same 5years we can have a beautiful story.
be thankful even though you did not invest in the beginning, but if you invest when the Ethereum price is still at $ 200,
of course you have made a lot of profit, hopefully you have already bought