I get that there are differing opinions on what “next thursday” means when said on a wednesday, but when you say it on a thursday, it definitely means “in seven days” and not “this thursday”.
Based on my experience it’s kind of unspoken standard that “next weekday” always refers to closest weekday occurrence where delta between now and that weekday is at least 6 days.
For me, I think it’s equivalent to “weekday in the next week”, so for me it could be <6 days, but then you also get into issues with Sunday 
Seems very culturally dependent: https://english.stackexchange.com/questions/3841/which-day-does-next-tuesday-refer-to
In any case, it’s definitely>0 days