Can you measure the size of your gas port? @98Z5V can calculate how large it should be and whether or not it is truly undergassed.
As @shooterrex said, your buffer is too light for a normally gassed 308AR.
At least my trigger has the company of the shot glasses. I know you are waiting for me to show up at your door. I am impatiently waiting for that as well. (Why don't we have a pants-down hug emoji?)
Welcome to the forum.
That is a carbine tube as has been said. The only way to get shorter is a pistol tube. However, you would need a shorter buffer of the same weight with an appropriate spring to get the same recoil. A possible option to get closer to the optic is the MFT Minimalist stock. They are available if you search.
Post a picture of your rifle so we can see it. What optic do you have? What is the eye relief supposed to be?
For those who have need of a reasonably priced LPK, these are available as of now.
https://www.righttobear.com/Polymer-80-Pistol-Lower-parts-Kit-LPK-p/p80-pfp-fkit.htm?Click=64422