how this will affect both BREXIT
Brexit is over and done with so it can't really have an effect on something that's in the past.
present-day
UK relations with Poland?
That depends on who his successor is.
kicked out of office for something g stupid like Covid parties.
That's not why he resigned. It's because of a recent sexual misconduct scandal involving Chris Pincher the Conservative party chief whip, whom Boris appointed to that very important role, though the guy already had a reputation. The latest episode and Johnson's mishandling of it is the straw that broke the camel's back, basically.