Hi there,
Definitely this workflow in conjunction with Tread, Chunk's way of going non-destructive as much as possible is the way I want to get better at. I've completed a few courses now in a short period of time. Even though I can now follow tutorials very well, when going solo I noticed it is different story (for the worse). I like the idea of creating non-destructive, then applying the modifiers in copies and converting everything into mesh, then going low poly in different copies, doing the UVs, and then texturing for a workflow. I am doing now some booleans, bevels, subdivisions exercise. I mange to get something very clean but it breaks when adding subdivisions. What do you think about my workflow to then get it into a proper mesh. Is there a way to upload my file in to here for you to see my settings?
it is also normal that when you're following a tutorial you feel like a god, it feels easy and you're like pfff I totally got this... then you try it by yourself and you become mush, like you forgot how to even click the mouse. So not to worry, it's all about practice and repetition, like in the gym, you have to get those reps in. The rules of modeling are very tricky, you need to have all quads and good edge flow to use SubD and that takes a while to learn.
I can only reiterate what Martin and Omar said.
Going at a project on your own will be tough in the beginning. The guiding hand is just not there anymore. Completely normal and it will get better with time and practice.
Your workflow in general is good, never hurts to have backup where the modifiers haven't been applied yet, so you can go back, when something goes wrong.
Like SubD on booleans for example. Martin said it pretty clear: SubD and N-Gons don't go well together and Booleans tend to create N-Gons for a living. So it either takes a lot of clean-up to get as close to perfect quad topology as possible, or manual modeling to have more control over everything.