Lewis N. Clark RFID Blocking Money Belt Travel Pouch + Credit Card, ID, Passport Holder for Women & Men, Black, One Size https://www.amazon.com/dp/B00I5IWC1E/ref=cm_sw_r_cp_api_i_AFKJ1ZAR254RPWWZQYQX?_encoding=UTF8&psc=1
I think they mean like this one. I just bought one.
I'd ditch the wired headphones. If your wireless lose battery power that quickly, get new ones. I love my Anker Wireless buds, they were only $40 and have a huge battery life.
I love having a big, light scarf-- it can be a blanket on the plane, warm for overly air-conditioned restaurants or evenings outside, and fashionable.
Lose either your crossbody or your mini backpack or your money belt. You definitely don't need all three. One of these is plenty! I've gone to using a small hidden pocket that can attach to my bra or pants or stuff in a deep pocket for emergency cash. Like this: https://smile.amazon.com/Lewis-N-Clark-RFID-Blocking-Hidden/dp/B00I5IWC1E/ref=sr_1_2_sspa?crid=24XDFYQXFF7GB&keywords=lewis%2Band%2Bclark%2Btravel%2Baccessories&qid=1659365690&sprefix=lewis%2Band%2Bclark%2B%2Caps%2C128&sr=8-2-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExNEhYVjJLUFVHOEZTJmVuY3J5cHRlZElkPUEwNjkyNTk0SVhCTlNZQUxURlVJJmVuY3J5cHRlZEFkSWQ9QTA4MDY0ODUxMFZCMVhUTzRaNUVFJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ&th=1
Otherwise, just put what you need in your day bag, whichever you choose. And I am a huge fan of putting stuff for the plane in the day bag, stuffing in a quick access pocket of the main bag while going through airport, etc, and then pulling it out on the plane. Also easy to pull out while going through security.
I second the raincoat. I think you're right Uniqlo will have something small. Marmot Precip is also a nice packable option that comes in black and looks pretty good. You can often find it on sale.
No need to bring the old phone as backup.
No need to pack liquid toothpaste, deodorant and conditioner. All of these can be found in solid forms. They also can be bought in any pharmacy when you get there, so there's really not a need to pack them on the way there, unless you really need to brush your teeth en route. Toothpaste tablets can even be cut in half, so you can bring less. To avoid bringing powder foundation, just use a solid tinted sunscreen.
Ditch your microfiber towel. As you said, your hostels will provide towels.
A few options.
Go to a tailor and have them sew in travelers/smugglers pockets to your existing pants.
They can only be accessed when you un button/loosen up your pants.
They are usually top open pockets to put extra cash or non bulky things.
Option 2. The travelers wallet.
Something like this loops around your belt and then gets away https://smile.amazon.com/dp/B00I5IWC1E/
Option 3: 5.11 or similar “dress pants”
I’d your office is looking for business casual to business dress, but not a suit, then something like these might work. I wore them with a dress shirt and tie for 5 years at a fortune 100 company. But we also had a lot of casual devs working in that office.
I tried the bravos but the material is too thin and the zipper thigh pocket stands out more than the open top thigh pocket on the edge chinos.
Kind of, but it doesn’t go around your waist.
Lewis N. Clark RFID Blocking Money Belt Travel Pouch + Credit Card, ID, Passport Holder for Women & Men, Black, One Size https://www.amazon.com/dp/B00I5IWC1E/ref=cm_sw_r_awdo_T81B1XWYRJHKSB2W3YSQ
I have this one: https://www.amazon.com/dp/B00I5IWC1E/
I like the Belt Loop Pouch approach.
Some good tips here: http://regevelya.com/taking-money-abroad/. I'd also look into a belt loop wallet https://www.amazon.com/gp/product/B00I5IWC1E.