In ranked matches, 1-bar connections are disallowed always.
As a side note, imo even 2-bar connections are generally quite good in Fantasy Strike and would maybe be called 3 or 4 bars in other games or something. For example, a 1-bar connection between California and Tokyo is mysteriously playable and pretty smooth, even though it shows up as 1-bar.
If there is a particular opponent you don’t want to play against because of connection issues, add them to your “avoided list” and you won’t face them.
If in casuals you play against a person, then are matched against them again afterwards, that in itself means there were no other opponents available. There’s already a big force in the algorithm that prevents matching twice in a row vs someone unless they are the only opponent around. In ranked, it’s actually impossible because you can’t face the same person twice in a given single elimination tournament.