I’d happily use diesel as a degreaser but I’ve not used it as a penetrating oil. It can work (see thread for instance)
Penetrating oils aren’t going to be at their best shifting a bearing that has seized into a frame though. They might help a bit, but if you can get to the back of it you’re probably as well just working round it with a punch and a hammer, not proper belting it but tapping – idea being to break the corrosion rather than blast the bearing out. Assuming the bearing cartridge is going to be steel and the frame alu, steel is harder than alu so just blitzing it out with a massive blow risks leaving a hole that a bearing doesn’t fit in as well anymore…
If you can get one on it, careful use of a slidehammer would be pretty ideal.