Well, I figured how to get the bold to work on my sideloaded stuff, which is a miracle in itself as I am pretty clueless about it all. Only thing is, its back to not having a cover show when I do it.
I use calibre only in the bare bones, I have no idea about any of the geeky stuff. Here someone said to first resize the cover, then convert to mobi "old" and use Pdoc in the field. That finally gave me the covers on my kindle on sideloaded.
I only sideload with the send to kindle thingie that I can right click on the file. Its the easiest for me and I can get my stuff in the cloud that way. I don't have a lot of sideloaded stuff really.
But it didn't have the bold font. So what I did was I converted to "both" mobi, whatever that means, I tried the azw, but I can't right click that for send to kindle. So now its sends it with bold enabled, but no cover. I'd rather have the bold I guess if I have to pick.