Honestly depends on the style of comic. A story comic where a decent amount of story happens on each page can get away with once a week. A three-panel gag-a-day can't. Or, for another example, a story comic with more atmospheric manga-style pacing needs more frequent updates so it doesn't feel like "nothing happened" after a month of updates.
My comic was designed to be read at one page a week, and when I first started uploading on Tapas at 3 pages, 3 times a week to get caught up, it ended up being so dense that readers would miss hugely important or obvious information that my weekly website readers had caught just fine.
So outside of like, what's ideal to attract people and not spam notifications (no less than once a week, no more than daily), different comics are gonna have very different ideals.