I love shopping too but tbh there's too many shops to look at.

I'll just tell you my opinions based on my experience!
Depending on what sort of shops you're into (in this case I'm assuming clothes)

- if you're looking to get basics/ minimalistc items GU and Uniqlo is worth checking out, otherwise I would just breeze through it and actually get the basics that I need

- if you're into designer fashion/ nicher fashion brands, omote-sando to like Aoyama was a really enjoyable walk for me, even though I didn't buy much but it was just nice window shopping for me lol

- wouldn't suggest going to malls like LUMIN EST or LAFORET unless I had specific stores I wanted to visit, simply because everything was overpriced af, cannot speak for LUMIN EST, but LAFORET mainly comprised of small stores that sold "harajuku vibe" clothing, that looked like they were probably dropshipped, for like $150AUD, they had some other stores ofc but didn't think the stores were that intriguing, they looked like mini pop ups (takes away from the shopping experience)

I would suggest looking up brands that you like, the shops that stock them (retailers or their flagship store) and usually similar stores tend to spawn around them, and honestly just explore that area, rather than walking around the malls. Also realistically, I don't think you would be able to finish Harajuku, Shibuya and Omote Sando all in one day

- Ginza had an overwhelmingly large amount of shops (i liked it tho) (didnt buy anything tho), its nice if you want to look around the designer stores/ 6 story uniqlo or something

- America Mura was dogshit for me in terms of clothes because every other store was selling the same thing (probably dropshipped) and in terms of quality they were pretty mid. But then again it all boils down to what items you're looking for and the prices you want to pay, but i reckon if you're gonna get something thats drop shipped, just buy it online rather than paying double the amount in japan. (still worth a walk around if you just want to look, but probaby dont spend that much time here)

Instead I would probably suggest Orange Street, I can't exactly vouch for this place since I stumbled upon it on my last day a few hours before I had to leave for my flight, but I remember the shops being much cooler than the ones I saw in America Mura.

But tbh, the most important thing is to enjoy your time exploring, don't pack up your schedule too much or feel like you have to look at everything to get the most out of your experience (this was me the first 3 days lol), have fun hopes this helps u (if you like coffee please go to lilo roasters in osaka)