The advice that most people don’t care to hear when it comes to giving a tree a head start and thicken it up is - stick it in the ground. No matter how green your thumb is, your tree will never thicken in a pot the way it will in the ground. Having said that however, there is absolutely nothing wrong with keeping it in a pot and taking the patient route. I don’t mind the idea of a tree taking ten years to get to the thickness of my thumb - it doesn’t bother me.
The tree doesn’t look bad. It does seem a bit 2D, so bending a couple branches to the back would help give it some depth. You have sort of a slanted style already established, so simply repositioning the branches to where they’re parallel to the ground would help bring it together. Also maybe shorten the lower branch on the left side of the picture if you can.
Other than that, just let it grow - it’ll have been through quite a bit and will need to recover.
That’s my opinion, but there are plenty of way more experienced folks around here that’ll be of more help.
Good luck!