Hi, i have files with several objects and i want to only keep those inside the page.

It's not about export, really want to delete the objects outsides without delete them one by one, so the clipping method + rezize page to drawing or selection doesn't work.

Is this even feasible ? Thanks for your help =)

There are several options for this:

If you do not need to cut any paths, because objects are either outside or inside the page area:
1. Drag a selection frame around the objects for each side and hit Del (so, 4 times)
2. Use the eraser tool in object deletion mode and just drag the mouse around.
3. Hold Alt + drag the selection tool around on the canvas to select the objects you want to remove. Hit Del.
4. Select the objects you want to keep, and invert the selection (Edit > Invert selection). Hit Del.

If you need to cut through paths:

1. Draw an object that covers the page area (use snapping when drawing it to be exact). Install https://gitlab.com/su-v/inx-pathops. Use the Intersection functionality.
2. Or do this without the extension. This will take a lot longer.