GIMP can open PSDs, but the format is not fully compatible with GIMP. PSD is a proprietary Adobe file format. It's not GIMP's native file format. Here's a list of the issues, and a possible solution which will require some manual work.
- Text layers in PSDs won't be editable in GIMP. Any text layers you
have will be rasterized when opening the PSD in GIMP.
- Only GIMP's native XCF format supports editable text layers in GIMP.
Photoshop can't export XCFs.
- Adjustment layers aren't supported in GIMP at all
So, the only real solution to your problem is to open the PSD in GIMP, and then create an XCF file using GIMP.
To prepare your PSD, in Photoshop you would need to merge down any layer adjustments so that you just have simple layers. When you open the PSD in GIMP, the text layers will be rasterized. But you could replace those text layers in GIMP with editable text layers. This would obviously mean retyping them or copy and pasting the text from Photoshop into GIMP, reformatting the font/font size/line spacing/kerning etc, and repositioning, then you could delete the rasterised text layers, and save the finished file as XCF.
Other things to be aware of:
- Raster layer masks seem to work OK when opening a PSD in GIMP. Vector
layer masks aren't supported. Vector shape layers aren't supported
either - so these would need to be rasterized.
- GIMP's layer blending modes are different from Photoshop's. So, when
opening the PSD in GIMP, if you have layer blending modes, you may
need to experiment with GIMP's native blending modes to get the
desired effect.
- GIMP doesn't support CMYK, so the image would need to be RGB, and
GIMP only supports 8bit per channel images, although there are
development versions of the software currently which support higher
bit depths. If you have Windows or Mac, and want access to these
development versions google "Parthas place"