Does anyone know about any company or firm that help crypto businesses with this ?
What is certain is that each region or country buys and sells Bitcoin and includes the risk of KYC, has different laws and ways for the security and convenience of customers and the Bitcoin user document itself.
In general, in my country it is legal to buy and sell Bitcoins, exchanges/companies founded by individuals and approved by the relevant government, about KYC we don't need any third parties like lawyers or Firms, who know Business only crypto users and crypto companies.
Although, you mentioned that crypto businesses in Sweden have firm partners or are easier to understand by notaries or lawyers, crypto users have a written agreement against the action of all forms of crypto buying/selling business risks, if I understand the crypto business law in Sweden.
I'm not sure what you're asking either:
Top Blockchain Development Companies in Sweden. or
Best Crypto Exchanges In Sweden (May 2022).