Some of the issues that you’re seeing (with QMapShack) are similar to what Allan Mustard had here with BaseCamp. I suspect that you have a number of problems:
- QMapShack is a bit limited in what it can render, compared with a real Garmin handheld
- The default mkgmap map style (which I guess you’re using) is a bit rubbish for area mappings - hence all your “factory buildings”.
- You’re making things harder for yourself by converting .pbf files to .osm. There’s no need; mkgmap can read .pbf natively.
People more familiar with QMapShack than I are welcome to leap to its defence of course - I did think about creating a mkgmap map style explicitly targeting it, but didn’t bother in the end because I couldn’t think of a situation when I would use it.
If you’re trying ti figure out how to do things better, this github page, this diary entry and this page might be helpful - and also Allan’s here.