1/Use Cable Ethernet (no wifi connexion)
Wired internet connections have fewer attack vectors than wireless ones, but they're generally just as safe as one another if setup correctly. You can go either way, really.
2/Create à virtual machine in which i’m Going to install Linux cuz as I heard window is not so good in term of security
It'll be better than just using Windows, but your Windows machine could still become compromised. Just using Linux (or dual booting, to a lesser extent) would be better, if possible.
3/Use vpn : which is the best for trading pc?
Anything that doesn't log your activity. A company that isn't based on countries that can subpoena data would be ideal.
4/Bookmark exchange website that i use and double check that the website address in the search bar are in the same
5/2FA Google Authenticator
I heard about RDP (Remore Desktop control),
What do u think? Is it really neccessary ?
Bookmarking is good practice, and so is using 2FA for everything that supports it. Make sure you don't use an online wallet, and don't leave money in exchanges.
What would you need RDP for? If you don't even want to use Wifi because of security risks, you probably shouldn't be using RDP lmao.