I do two pages of Errant a week, and my ideal schedule goes like:
Friday-Sunday: Rough and then neat pencils. Ideally all pencilling should be done by the end of Sunday. It's close to impossible to estimate this, because this stage can also include things like "building or sourcing 3D models, getting photo reference for backgrounds, designing stuff" etc And a page that's a few panels of faces will take a lot less time than one with several panels of scenery of multiple people in a room etc. It takes as long as it takes, and I also fit in whatever other life things need doing around it.
Mon-Tue: No comic-making, dayjob
Wednesday: I try to get all my inking done. Inking both pages usually takes around 2-6 hours depending on complexity. Sometimes I start the colours here too.
Thursday: Colouring, lettering and uploading. I'm usually done by tea time unless I have outstanding inking from the previous day.
I could estimate that Errant takes in the region of 4-12 hours per page maybe? But also doing them in batches of two speeds the process, and I have a very loose process built around hitting targets by deadlines rather than spending a specific number of hours, because that's the best way to hack my neurodivergent brain into getting things done. If I hit hyper-focus, I might get a page inked in as little as an hour, but if my brain throws a wobbler, getting the inking or colours done is a painstaking process involving chipping away a panel at a time while trying to manage over or understimulation with music, rain noises, stim toys etc.