Since you’ve been to several of the top places in Asia already, and you love it, I think Bali might be your best bet. As I’ve written many times recently, I feel that the main tourist area of Kuta/Legian/Seminyak is just too crowded and overdeveloped to recommend, although it is interesting for a couple days and some nightlife. The arts and crafts town of Ubud is still nice, although also a bit crowded, but it’s not anything like a city so I still think you’d enjoy it.
Keep Snacks Handy When You are Out – This was my snack stash for Disney World. I had Macadamia Nuts, Walnuts, Pecans, and low carb bars. I made sure to chill the water bottles in the freezer beforehand so that as they thawed throughout the day, we had cold water. When hunger hit, instead of falling to temptation, I just grabbed my bag of snacks before I got HANGRY. Doing so made it so much easier to make keto/low carb choices at mealtime. I kept my snacks simple because we already had enough to bring with us (if you have a baby and a toddler you know what I mean). I saw lots of people with small coolers who were snacking on fresh veggies and deli meats, but, again, my goal was easy breezy. You can find a great list of Keto/Low Carb Snack ideas here for inspiration if you prefer a variety.
Southeast Asia is easier to deal with, and there are cheap flights connecting in the Middle East and landing in Bangkok, Kuala Lumpur, and Singapore. Each of those is a very interesting city, and there are many smaller places to go in the same region. In Malaysia there is Penang and Melaka. In Thailand there is Chiang Mai and quite a few others in that area. In Laos you can visit Luang Prabang, which sounds like it could be a winner for you. And there is also Siem Reap, which is home to the amazing Angkor Wat temple complex.