I often say "perfect is a goal, not a destination," so we are in agreement. Now, to the examples!

After seeing the success and failures of the 20th HardFork I have logged in

The word "have" is redundant. It makes the sentence present perfect, and it should be simple past: "I logged in."

I and wanted to find out what can be done so that HardForks are tested better so that the changes are implemented smoothly.

A few issues here. Starting with that redundant "and" at the start, which I guess may have been left over from a different form of the sentence? There's also no punctuation. Punctuation is good!

@gtg, the wizard of Steemit proposed to making own TESTNET and stated that it is needed not only for hard forks.

Whose own testnet? @gtg's? All of yours? Also, again, punctuation. Let's do a sample edit:

"@gtg, the wizard of Steemit, proposed making our own TESTNET. He stated that it is not needed only for hard forks." (A comment here: I guessed at @gtg's gender based on Gandalf being male. I would have considered using the singular they if it were my post and I didn't know the gender).

so that the new hard/soft forks are bulletproof before actual implementation.

Let's make this simpler and more accurate: "So that future hard/soft forks are bulletproof before implementation."