So if farsight holding something for themselves, i say i am ok with that, still it does not help to understand the plan and why "good aliens" plan to do this in our lifetime?

Once again "good aliens" start open confrontation of bad aliens.
The bad aliens will get out of all hidden places on Earth and the war probably will be everywhere, and the contest for star killer weapon begins as new, do we want this mayhem ?

I sincerely not , the best approach would be to attack our enemies at theirs home worlds deploy antimatter bombs and make sure they can't travel to us from any point of galaxy. This would be more humane and less dangerous for all humanity on Earth.

But "good aliens" insist to bringing the war at our doorstep leaving us without any means to fight and empty promises of peace, if this not suspicious enough what else?

What i think actually happening, the "good aliens" , they know if they get control over the very ancient star killer weapon, they will not grant access to us, but they will use it as some sort of a ledger against "bad aliens" , then bad aliens get out from our planet , but they will try to makes sure that we suffer and they will try to bring theirs armadas to our region of space, it may take them ages , but eventually they try to do that, so the plan of good aliens do not resolve the current problems on Earth it makes even worse!

Logically to question : so why we letting "good aliens" to decide our fate?
Why humans cant decide here for ourselves what the best for us?

Good E.T.'s aren't deciding human-fate; they do provide wisdom, but, humans must make the effort and decide to actually make use of such wisdom for themselves, rather than let opportunity be squandered.

Authoritarians (Bad E.T.'s) on the other hand _do_ «decide» the «fate» of humans/humanity;
The authoritarian-minded types actually do NOT let humans «decide for themselves» as is evidenced by the «COMPLY with OUR ORDERS or DIE» attitude that is so frequent of them...

Fear is amongst one of the most-effective control-tools of the Dark Sovereign Power (the Core-Source of All Authoritarianism). Nor have nor are the «Good E.T.'s bringing war to Earth's door-step» since humans have actually ALREADY been at «war» /against/ the «Bad E.T.'s» for decades now.

https://www.bitchute.com/video/xgNjX1NKN3o/ (Duration : ~04m06s)
Video-Title : PHIL SCHNEIDER: GEOLOGIST- "THERE IS A WAR UNDERGROUND."