Slightly tells me that I know bitcoin from this forum around June 2017,
But I haven't kept up with the crypto world for a long time due to my busy business and boredom with the price of BTC in 2019.
So I almost forgot all my assets until there was one. the thing I think is my stupidity, I omitted my Trezor which still contained around 9 ETH at the time I bought ETH around $ 700 in mid 2018, and ETH keeps dropping so I ignore it.
Long story short I want to start from scratch I want to ask the seniors who are here.
I want to start trading again. Could you please give me some advice so that I don't go through things like a few years ago.
If you lost your Trezor with 9 ETH, yes it's better to restart than to never again reneter this fast-growing market. I'd focus on gradually accumulating, and you will have plenty of opportunity to do so next bear market (we may be entering one right now). Take your lost ETH as a learning experience and focus on BTC and other solid coins (I think ETH is one of these, but you have to keep abreast with developments in case ETH loses its position).
I also do not suggest trading. I suggest investing and focusing on the long term.