Just for perspective, Brannstrom and Linus Arnesson (2013 60th overall) are the only U24 defensemen in the SHL who were drafted in either the 1st or 2nd round of the NHL draft as far as I could tell. Most 1st and 2nd rounders have moved to either the NHL or AHL.
Filip Westerlund also played in SHL for a bit, who was drafted 44th overall.
There have only been 7 Swedish defenders selected in the first two rounds of the draft since 2015 - so you're going to be hard-pressed to find any defensemen that were selected in the first two rounds, playing in the SHL right now.
Erik Brannstrom - D+1 season, playing in SHL
Timothy Liljgren - D+1 season, playing in AHL
Gustav Lindstrom - D+1 season, playing in Allsvenskan
Filip Westerlund - D+1 season, played in Allsvenskan/SHL/SuperElit
Oliver Kylington - D+3 season, playing in AHL
Rasmus Andersson - D+3 season, playing in AHL
Gabriel Carlsson - D+3 season, playing in AHL
Lindstrom/Westerlund aren't good enough to play in SHL regularly.
Kylington/Andersson/Carlsson are in their D+3 seasons, so no reason to be in the SHL.
Liljgren is the only example, other than yours from a 2013 draft (and there's a reason he's still playing in the SHL at this point), that moved on to the AHL when he could've played in SHL if Toronto wanted to go that route.
So I'm not sure what your point was? There is only one comparable example to Brannstrom, and that would be Liljgren - there's been limited Swedish defensemen drafted since 2015, and most either aren't good for the SHL due to being drafted later, or are much further ahead in their development.
It's highly unlikely Brannstrom is still overseas next season. Makes me wonder if Vegas didn't have a joined AHL team, if he would've been over here for this season.