It’s too bad this has happened. But it might be easier to fix it should you decide to go on a slightly different route.
If you posed the upper engine panels open, it would probably be very hard to notice the gap. Plus it would show off the engine which looks great on the Zvevda kit.
I would seriously consider displaying this 109 with the panels open showing off the internals.
Just my 2cents.
How hard is it going to be to cut the upper engine cowling along the hinge lines ??? You can easily fabricate a support rod for each side with some round stock or possibly even with some heated stretched out plastic sprue materials.
The new Tamiya 109 has two different panels and one is molded in the open position.
I found this photo online and it looks great this way.