From those scans, I don't think you have a development problem. You should consider continuous agitation instead of the classic 10s/minute arrangement, but they don't look uneven or otherwise problematic in the chemistry department. It looks like you've got your scanning black-point sorted better now, so I reckon with about one stop more exposure you will be getting wonderful results. Don't give up on your process now!
Giving up is not an option! But I have developed another roll now and I still have some magenta/purple things on the sides. I'm pretty sure it's on the negs. I don't think I have got that on every roll so that problem together with bad scanning made it hard for me to sort it out. Anyway, a scanner is ordered and with some reference material from a pro lab I think I might be able to pinpoint the error better. I'll be back!