I was listening to a talk by a European astronomer recently, he reminded the audience that one of the changes that is about to happen in Europe is the ending of changing the clocks. The European parliament carried out a consultation about clock changes and the Germans voted for it to stop ( 70% of the responses were from Germany - the other EU countries including the UK managed 30%!). As a result the EU parliament have declared that clock changing will cease in 2021. However each country has been given the choice of staying on permanent Winter Time or Summer time so two adjacent European countries can have times that differ by up to two hours. As far as I am aware the EU countries have not yet individually declared if they are staying on Summer or Winter time.
Of course the UK does not have to follow this directive (depending on the withdrawal agreement) so may keep changing to Summer Time.
The biggest effect other than speaking to people in Europe will be to those who sell / use Radio Controlled Clocks. They will need programming for each countries time zone and of course if the UK keeps changing clocks you will not be able to use the UK radio signal in euro and likewise will not be able to use the German signal in the SE of England where it is often stronger than the MSF signal from Althorm.
Of course all the computers, phones and GPS’s will require changing to accommodate this as well.
What fun politics brings to time !