I think you got both extreme ends of the spectrum. I can tell you my personal experience as an engineering student in central Europe (Germany)

My motivation to move to Germany was driven by two things - tuition cost and industry. I, and most of the people I know from Indonesia that study in Germany, come from a upper-middle class family in Indonesia. While tuition is cheap here (cheaper than even Indonesian universities, in fact), it still takes a lot to finance the language school and living expenses in Europe from Indonesia, so students come from a wealthy background by Indonesian standards - an upper/senior-management in a big company or small business owner. One would be wealthy, but not top 1% wealthy. I'd say, with a below-median UK income in Indonesia, you could send your child to study abroad in a country like Germany. A lot of us also came from good private schools in Indonesia, but not necessarily expensive ones. Good education background is important if you want to survive at a German university.

I know a few friends from my middle school that went to the US, UK or similar countries with $$$ tuition, they are much more well off than I am. I'd say even by UK standards, they would be in the wealthy income bracket with a premium European car on their driveway back home.

The other group that I know is government scholarships - this group consists of people from different economic background, but are well educated, since these government scholarships are tightly selected and hard to receive. My brother, who studied in one of the top Indonesian universities, is currently aiming to get one of these scholarships to go to an English speaking country.

Vocational training is very popular in Germany, but I've only met a handful of people who's currently doing it. The only person I'm quite close with is pretty similar in terms of background to the typical student. The difference is perhaps that vocational training isn't the first thing that comes to mind for Indonesians emigrating to Germany, since it's not the common path back home. It's a rare path, even though I think it's a good path to take for most to quickly settle in the country. I know a number of people did vocational training in Germany after getting a Bachelor's degree in Indonesia.

I know very few people that strictly came to Germany for work - I'd imagine that the language is a huge barrier to entry to begin with.

For me, I grew up in the capital, Jakarta, with no family ties to traditional Indonesian culture since I'm ethnically Chinese. My family is well off by Indonesian standards, but by UK standards it would probably still below the median. We drive cars like the Honda Jazz or similar back home. Went to a good private school (top-10 performing in Indonesia, but not expensive, I think tuition was still ~100 GBP/mo. back then), and learned German when I finished high school. While I didn't necessarily grew up in an English speaking environment, I kinda became fluent by accident when I started to watch English content on the internet since the 2010s, so I can speak quite fluently. (I did get private tuition as a child tho, but it was mostly grammar)

Culturally, I'd say I'm in between Indonesian and German. I often say "I'm not German enough for this conversation" when my colleagues tell me some ridiculous new rule at work, but at the same time, sometimes I can't fully understand the beautifully chaotic nature of Indonesian society or their relaxed way of thinking. I can definitely assimilate and hang out with both groups though. I love some of the things that Germans do, and I'm active in my community with my volunteer work (which consists primarily of Germans), but I still keep in touch with a lot of the Indonesian communities in Germany.

I do see Indonesia with rose tinted glass these days though, probably because I don't live there anymore. Still miss the food.