Yeah, Landeskog seems like an obvious choice. He has yet to captain Team Sweden though, he was assistants at the 2014 Olympic and 2017 Worlds.
I'd probably go
C - Landeskog
A - OEL
A - Bäckström (if he plays) otherwise Hedman
Just for the fun of it, I went through all the leadership groups since Zetterberg played his last tournament
2014 Olympics
C - Niklas Kronwall *promoted to captain when Zetterberg withdrew
A - Daniel Alfredsson
A - Gabriel Landeskog
2014 Worlds
C - Joel Lundqvist
A - Mikael Backlund
A - Jimmie Ericsson
2015 Worlds
C - Staffan Kronwall
A - Joel Lundqvist
A - Jimmie Ericsson
2016 Worlds
C - Jimmie Ericsson
A - Mikael Backlund
A - Erik Gustafsson
2017 Worlds
C - Joel Lundqvist
A - Victor Hedman
A - Gabriel Landeskog
2018 Olympics
C - Joel Lundqvist
A - Staffan Kronwall
A - Erik Gustafsson
2018 Worlds
C - Mikael Backlund
A - Oliver Ekman-Larsson
A - John Klingberg
2019 Worlds
C - Oliver Ekman-Larsson
A - Mattias Ekholm
A - Patric Hörnqvist
2021 Worlds
C - Henrik Tömmernes
A - Rickard Rakell
A - Klas Dahlbeck
2022 Olympics
C - Anton Lander
A - Henrik Tömmernes
A - Marcus Krüger
2022 Worlds
C - Oliver Ekman-Larsson
A - Adam Larsson
A - Joakim Nordström