Creating my own opening?

It's not the best imo because you've blocked all development for both your bishops and queen. Your opponent can easily take control of the centre by following the engine lines. You need to be more focused on putting pawns out to the centre, and developing your bishops as early as possible.

My own Jazbec Gambit

Looks Good, I will try to play it once

1.e4 e6 2.d4 d5 3.Bf4(I named it the Adam gambit) 3. ...d×e4(Adam gambit accepted)or 3. ...Be7 4. Nc3(Adam gambit refused)4.Nc3 Nf6 5.Bc4(Adam gambit accepted: main line) or 4.Nc3 Nc6 5. N×e4 Be2 6.Nf3(Adam gambit accepted : boomerang variation)

Or 5.Nb5 (magnet attack) and by the way, why is it a blunder ?

Englund gambit declined, reversersed french, queen's gambit varieation.

If I suspect a new chess opening variant, where can I check if it doesn't already exist? And if it doesn't, where do I go to officially give it a name?

English Opening: Reversed Sicilian: Danish
Invitation

I have never seen somebody do this but yeah, Its an invitation to the Danish. Hooray!

Reti Opening: Krejcik Variation

No dumbo dumb dymbo

I see that you didn't use the "analysis" button. Most of the opening suggested here do not give an advantage of +1 or more to each side. "You cant do your own beacuse it exist" "You showed so bad moves where are a lot of bad position" Most of the openings do not already exist, though it would be a stretch to call some of these "openings"

English Opening : Kings English , Reversed Marshall-Keres Franco-Sicilian Variation

You can use the amateur database and filter games close to your rating. There are a lot of really cool sidelines in amateur games if you use a database. Analyzing my 1.e4 e5 2.f4 f6? Games, I found this devastating line: