"Level of detail" is something very relative. For one you're comparing to manga that are older and tend to have less detailing and then gain detailing as time progresses. There are also other manga like Berserk where detailing is everywhere, and compared to that Bleach has none.
Also the main thing with the less shaded manga: the shading is their linework. The thick and thin lines are what gives the work it's volume and 3D aspect, whereas you're working in consistent thin lines with no width variation, so in your case shading is necessary to get a sense of 3Dness.
Rule of thumb is the more your lines are visible and carry info the less you need to do for shading to make the drawing pop. Your lines currently carry very little info, so you can work on your linework if you want to do less shading, or work on your shading to keep your linework unchanged.
I'm in the same boat as you: part time, no budget, no assistants, I write and draw my comic by myself and I often get behind schedule. However I've gone in the opposite direction because I love shading and detailing, I've just accepted that my style takes longer, as long as I keep going at a slow but steady pace, the pages will come out, and I've got a whole book out now like that so it can't be that bad of a method for me. Plus with practice I got quicker with this more detailed style, so I was able to put more details in and work on really creating a world that was lived in and looked good.
Example page from my comic for what I mean when I say "detailed", most pages in book 1 are like this, and book 2 I'm working on has more backgrounds right now.
