Okay so I left v0.16.0 and focused on v0.20.0.
I successfully build v0.20.0 using this guide, the problem is that I don't know if I have successfully created a new blockchain. When write getblockcount I get 0. Although it still shows me that I'm connecting to peers. Before I compile I had removed every single line starting with vSeeds.emplace_back so I don't make sense. I also had changed ports. (8333->6333, 18333->16333)
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At very least, changing port won't let you connect to different blockchain/network. You can change the port and connect to Bitcoin network without any problem, especially since there are few ISP that used to block port 8333.