The UK Ancestry Visa page ( https://www.gov.uk/ancestry-visa ) says I need an offer
That is not correct. It says that you need "evidence that you’re planning to work in the UK."
It then goes on to give examples of such evidence, one of which is "job offers you’ve received."
You can submit other evidence instead, but I do not know how ...
The Answer posted by @phoog is correct, and is explained in more detail by the UK Ancestry Guidance cited in Traveller's comment. Page 17 of 37 of the Guidance says:
The applicant does not have to be working at the time they apply. They need only demonstrate they are able to work and intend to take and seek employment. Evidence of this could include, but is ...
As I have received Blue Card finally I am updating the answer for anyone interested:
Once you reach Germany on German national Visa, do the following (based on my experience)
Get a flat/residence. make a rental agreement.
Go to the City office and register to get 'Anmeldung'.
Get health insurance and obtain a certificate for the same.
Obtain an appointment ...
"What are the tax implications of remaining an employee of a US company in Canada?
If you become a tax resident of Canada then, as far as I am aware , you can not be employed by a US company. In very broad strokes, employee as a concept only works domestically in general everywhere. You'd need to become a contractor or you company would need a Canadian ...
The first sentence of § 81a AufenthG reads
Arbeitgeber können bei der zuständigen Ausländerbehörde in Vollmacht des Ausländers, der zu einem Aufenthaltszweck nach den §§ 16a, 16d, 18a, 18b und 18c Absatz 3 einreisen will, ein beschleunigtes Fachkräfteverfahren beantragen.
The EU Blue card is controlled by § 18b so it is covered by the fast-track procedure (...