I’ve had quite the opposite experience, and I think the main reason is eating habits. OP, you mentioned you cook most of the time. Keep that habit at all costs. Taiwan will lure you to eat out for practically every meal. Prepared food is everywhere and cheap because of an overwhelming number of street vendors. Furthermore, the structure of the cities is housing above, restaurants and shops below, so it’s always at your fingertips. A decent job will land you a decent enough salary where you’ll feel, “aw, what the heck, I can splurge a little”, and if you’re not careful, you’ll do it all the time.
To compound this, the apartments, particularly the kitchens, you will find here are puny and under equipped. It’s hard to feel compelled to make a home cooked meal with one burner that works only half the time but only if you first step outside to turn on the gas lever and make a mental note to turn it off again when you’re done so you don’t end up as another far too high Taiwan gas explosion statistic. In most kitchens, you’ll barely have room to turn around let alone store any cookware. The water pressure may be so laughable that you won’t feel like spending three times as long doing dishes. A plethora of bugs will invade everything you’re not anal about sealing.
Even more so, Taiwan isn’t like Korea in the sense that you’re not expected to learn the language. The vast majority of foreigners here, even ones who have been here for a long time, can’t speak the language. It’s because, unlike Korea, most people here speak enough English to communicate, so you can get by without Chinese. This will translate into your food acquisition habits. Since your Chinese will likely suck, and you certainly won’t learn how to read (it’s not easy and sensical like Korean, they use traditional mandarin characters here), you’ll be deterred from going to a grocery store to try to figure out what everything is when you can just pop into one of a slew of nearby places with an English menu.
However, this is preventable; you can cook your meals and save money, and you should. When you look at apartments, go right to the kitchen. Check for two burners, roominess, water pressure, comfort, a fridge (most are mini fridges… again, a deterrent to cooking), and a relatively new water heater (usually on the balcony). Buy decent cookware, tupperware, and bag ties to seal your food. Force yourself to go to the grocery store early on and often. Learn what’s what, and what’s available and what’s not. If you’re a vegetarian like me, it’ll be particularly hard. If you’re not in Taipei, it’ll be hard to find many of the traditional staples of a western vegetarian diet, like canned beans and lentils. You can find them, but they’re often not at the grocery stores; they’re at the specialty stores. Walk around and ask around and find where these stores are early on. Same thing with free range eggs - you can find them, but they’re usually not at the grocery stores.
It’s actually a dangerous combination because Taiwanese restaurants use boatloads of MSG (wei4 jing1) in their dishes. In Chinese, MSG is translated to “the essence of flavor”. The food here, partially because of the MSG, will take its toll on your body, and your health will suffer as a result. Since coming to Taiwan, I’ve developed stomach ulcers, acid reflux disease, and am on constant medication for it. Never had a problem like this in the States for the first 30 years of my life. The prepared food will likely fuck you, given enough time. This was the primary reason a foreign friend of mine who had lived here for seven years left to his home country. Several of my foreign friends have come to the same conclusion and feel forced to exclusively cook all their meals at home. It’s probably other things like certain strains of bacteria in the food, but who knows.
TLDR: If there’s one thing I wish I did differently in the past three years since my arrival, it would have been to (re)learn how to cook my own food here. I started doing this last month and already see a huge difference in expenses and personal health.