Old Skier
Tour Winner
Why did the EU set the timelines?
Possibly to try and control the outcome, you'll need to ask them.
As there are red lines on both sides then perhaps a more sensible approach would be to agree on what they agree on (which has happened in a number of cases but doesn't seem to warrant much coverage in the media) and then argue about the trade and other red lines when, because of the rules laid down by the EU, cannot be discussed until after the end of March.