Sunset Cruises - Lisbon

Since you haven’t received any response on this, I will suggest taking a ferry ride in the late afternoon from Lisbon to Cacilhas, enjoy a nice early dinner there and take a ferry ride back just around sunset.

I can’t help with a formal river cruise in Lisbon.

We’re traveling at the same time and researching river cruises as well. Have you found any preferred companies?

Haven't used this company but they have sunset cruises
https://www.frs-portugal.pt/route/sunset-cruise

We have used yellow bus, they have port sightseeing cruises but not specifically sunset
https://yellowbustours.com/en/lisbon/river-cruise

We also used the ferries to visit both sides of the river
https://ttsl.pt/passageiros/diagrama-da-rede/

I have seen several options for these cruises on Viator and Get Your Guide sites.

Thank you for your suggestions.