I've been thinking about "dress for the job you want, not the job you have" as I was putting on collage pants, sports shirt and construction work socks. How should I dress for the job I want, which is software research and development?

I do want to separate myself from the sales so noone gives me any of those duties. I'm comfortable working with existing customers through Slack and such + the occational development meetings, but not more then that.

Dude, just get dressed, no one feels comfortable talking with a naked guy

Just some personal hygiene and maybe clothes that make you look like you care what you're wearing

As comfortable as you can within business requirements. Just like programming baby!

You can't be overdressed. But surely underdressed. So do some research on "Business Casual Style". The thing is if you wear a suit and there is a social situation where you feel overdressed, you allways can take of the Blazor and fold up the sleves of your shirt. Get one or two bespoke tailor made suits. And since you live up north, the swedes are masters in dressing sharp for business so a shopping trip to Stockholm maybe? If not in Hellsinki there are some Tiger of Sweden stores.