I still do not understand why people use PhotoUseItForWhateverShop. There is a lot of questions people using it wrong, rasterizing assets, using a wrong resolution, flattening stuff, etc.
In my opinion, this part should be made in a vector based program. Illustrator, Corel Draw, Affinity Design, even on Inkscape.
The advantages are that you have resolution independent assets in many regards.
The problem is: People actually use PhotoShop to do this. So you have to deal with it.
But I think we do not have the same concept when you say "concept of the Page".
One step is the layout, the first step. This first step has nothing to do with interaction. That is an additional step.
As a developer, you are probably used to just pull a Script and paste it on the spot. That will not happen with PS.
How can I learn good PS habits to be actually time efficient when making a Website
Ok, this is too board. My answer would be... Put simple objectives and practice. But the problem I see is that I really do not know if you have a clear concept of "design". Is design simply move boxes around? Or you want to explore different treatments of images and spaces to mean something an solve a communication problem.
And is the time to learn it even worth it?
Probably yes... That is why there are zillions of tutorials and users... using it right way or wrong way but that is another issue.
where I'm the Solo Dev + "Designer" its the perfect time to move and learn new stuff which helps me to be more efficient in the future.
A more efficient way could be not working alone. I think you want to live in your own echo chamber. If you are working alone, it really does not matter what you use. I would look for some other tools as Joonas commented.
Tools are always evolving, so again Is the time to learn it even worth it? PS or any other tool. I say yes.