All

it depends what you're reading, everything uploads at different times

Depends on a a lot of things....depends on if the entire manga is out and it just means the scanlation team is slow
Depends on if the scanlation team even has the raws to more chapters, they could drop it
Could be that the Japanese author hasn’t continued the story yet

It depends on their scanning team. If a scanning team has more members it will update faster. A scanning team with less members will take longer than a team full of members. Mangas usually take about one week to update. You can check when the chapters were uploaded by clicking a manga and scrolling down.

There's no universal uploading date. Each manga has their own scanlation team. Sometimes, an occasional passerby uploader takes screenshots of officially translated comics.

Thank you