Since you've already tried carry on only and it worked, why not do it lol. You have a month, so a day of shopping for items you might have usually brought in checked luggage, is no big deal. I have greatly scaled down what I bring. Not quite at carryon yet lol.
Last trip I only brought jewelry that will fit in a 7 day pill keeper. 3 chain lengths, 2 pendants, 2 earring sets. one extra watch. Don't care if people see me in the same jewelry lol.
The washer & dryer is my thing too. You definitely don't need as many clothes that way.
I think you said one time that you use Lancome facial products. Lans sells Lancome, but maybe not everything. I've found that the little sample jars from Lancome are enough for nearly a month of various facial products, wisely used. I'm picky about facial products so I have to take my own since my skin is sensitive. But I've worked it out.
I found some great little easy squeeze pop top bottles on Amazon that hold about 3 oz. of liquid such as for my face wash. They stay tightly closed in flight. I also found that the sample bottles of my shampoo and conditioner last longer than I ever thought they would.
Like you, my meds for that long and my water pic take up space, not much to be done about that. I do like to have Pepto/Imodium on hand lol. Also did you know that at least in the US, liquid meds such as eye drops, prescription nasal spray for allergies, etc. does not have to go in THE 1 quart allowed baggie. They are allowed in a separate baggie. That info changed my travel life lol.
Freddy's Pharmacy has a lot of sunscreen. He also has a lot of other things. But if Cera Ve body moisturizer is available at La Comer, I can tell you it's very good and is unscented. Good stuff!
I have a body moisturizer combined sunscreen that was recommended by my dermatologist. Don't know if it's in PV, but it's Aveeno Protect & Hydrate SPF 60. Even here I have to order it though.
I sewed a second wide piece of twill tape higher up onto the back of my backpack, so it easily stays on my rolling carryon. I also sewed a loop of less wide twill tape onto the top of my backpack so I can hold it if also necessary with the pull handle on my carryon.
Like you, tops and bottoms etc. are limited to what I can switch around...goes with almost everything. Therefore, I only take 1 neutral pair of sandals for evening, 1 neutral pair for day, flip flops for the beach, and I wear my athletic shoes on the plane.
I take my thin lightweight hoodie which is a very light grey (goes with everything) and is not like the bulky athletic type. It is the only long sleeved thing I take for possible needs later in the evening, and I wear it on the plane.
Hope something here helps you!