(edit title) immigrating as a contractor How to be compliant with all the rules? Options

[*Guest*]

So, here's the mess of a situation I'm in:
-italian passport
-resident in Poland
-working with a firm in UK
-wanting to relocate in Sweden
Now, to complicate the matter further, I'd need to start working months before relocating, which means that whatever I do to register as a contractor I need to do from Poland.

I've read that an option is to make an LLC and then open a branch in Sweden... are there alternatives?
Does anybody know of any services that can help me deal with all the bureaucracy, accounting, tax payments, rules, regulations, compliance etc?

As a sidenote: the first thing I want to do after relocating is look for a house to buy, I heard that in the stockholm area the housing market is kinda weird, are there any special rules for it (IDK, queues, mortgage requirements...)?