Upvote:3
As long as you travel before 31 December 2020, there will be no consequences for customs as the UK and Portugal are both within the EU Customs Union, VAT area, etc, so there are effectivley no restrictions on personal goods between the two countries.
As for if you can travel with such items - the general guidance is to consult your airline's and airports on routes guidance. You haven't specified your airline, so for example see British Airways: https://www.britishairways.com/en-gb/information/baggage-essentials/liquids-and-restrictions
There is no mention of computers, game consoles, monitors or displays as banned or restricted items at all (so you could take them as hold or hand luggage). Anecdotally these are perfectly normal things to fly with, although it will be difficult to pack your monitor safely.