Will Brits covered by the Withdrawal Agreement, be able to register a new 1-man Company from 2021?

It can be learned from an analysis of the Withdrawal Agreement concluded between the European Union and the United Kingdom (art. 25) and from the Act on the amendment of the Act on entry to the territory of the Republic of Poland, stay and leaving this territory by citizens of the EU member states and their families, and some other Acts (signed on 21 December 2020 by the President of the Republic of Poland) that British citizens who had been residents in Poland prior to 31 December 2020, (i.e. the expiration of the transitional period) will be entitled to perform business activity in Poland.