What kind of tree do you want to make/ what do you want to achieve?
You could build a tree from the lower branch and use the top as a sacrificial?
You could wire the trunk for movement?
You could stick it in the ground and leave it for 5 years.
I don’t know how well it back buds? For me, I would be looking at getting the trunk bigger, so fertilise heavy and get it in the sun to build foliage.
Need to know what the growth habit is first . The needles on the trunk it self do i take them off .
This is an elongating species. Like what Andy said, fertilize heavy. Don’t do anything to it yet. Look up info about frasier fir online, then filter the library in the live stream to fir or elongating species.
If you feel the tree is healthy (looks it to me) you could wire the trunk for the movement you envision in the future, and also work on keeping the tree healthy and growing.
What @JamesP said.
The trunk will only get thicker and it looks as straight as an arrow.