Agree with this. I think one of the reasons the Scottish teams (aside from the OF) tend to struggle in these qualifying rounds is that a lot of the potential ties are against teams that play their seasons over the summer period, and tend to be more match-sharp when the qualifiers are played. Killie v Nomads in 2019, Motherwell against Sligo a couple of seasons ago etc
Not saying it's the only reason why this happens but I believe it's one of the main ones.