I’ve exported from DesignSpark and Eagle, both should be fine once you get the file naming and format sorted out. If defaults don’t work, play around with the settings and if stuck ask questions here.

If you already use DesignSpark Mechanical then that may be the easiest path for you.

I started out with Altium years ago when it was Protel, inherited a bunch of stuff in Eagle so had to become familiar with that, played around with DesignSpark for some larger boards outside my Eagle licence limits, but if I was starting again now would probably go with KiCad.

As I recall there is a check-box in DesignSpark to allow you to do this, but also if you get the Gerber suffix right the Voltera software will do it for you.

I’ve been using KiCad for my V-One projects. It is open-source, and very friendly for creating custom footprints especially for through-hole components and headers to accommodate rivets. The only limitation I’ve dealt with is not being able to create hatch planes with the current version, but I believe it is coming as a feature in the next major release.

Yes, the new version is so much more capable.
I downloaded the overnight build V5.99 just to convert the solid planes to hatched and generate Gerbers.