Can you be more specific? Most of us here do 100km ride during weekends… (well it's the only time to do anyway)
Plenty do 200km in a day too…

Frankly, to do 100km in a day is actually quite a feat for folding bikes. It's no problem for road bikes as their bikes are designed for aerodynamics and they weigh averagely 8 kilos only. Also most of their wheelsets are not more than 2 kilos with tires. This makes the rolling very much smoother. Coming back to folding bikes, to assemble one less than 12 kilos will take bucks and bucks of dough. So, don't expect a 1K or 2K folding bike to be sub 12 kilos. Doing 100 km, entails  very reliable components and this also means more bucks. Even some of our friends' foldies of forummers within here, I can guess their toys cost more than 5K when they assemble.

It is easier for us that tinker with our own bikes. If you can't, it will cost a lot more for labour charges to send to LBS for some upgrades or even more for mods.

In your case, Dahons and Terns which meets your requirement to be in the 5K or more range. Even if we start with a Dahon Route, which is now selling for 1.6K is shodded with the basic 7 speed. And even with this, after some basic mods on it like wheelset change, groupset change will come back to square one, more than 4K. So, your best bet is Java. They are the ones that captures your segment. They will get bulk OEM components and make their frames either tough or light (you choose one  ) and fit in 16 speed or 18 speed. Never 20 speed though because 20 speed is still relevant in biking circles so the 8 speeds and 9 speeds are much cheaper to get their components. But it does serve the purpose nowadays as companies like Sunrace makes cassette with their higher end range. So, technically speaking, 16 or 18 speeds actually performs the same as 20 or 22 speeds if you get the right cassette. Then again, higher ends and more lasting or robust components are all 10 speeds and above nowadays.

Faster go to Lerun Warehouse, Tern B7 selling for RM750...

all in less than RM1.4k, using ezbuy, however dun recomend ezbuy anymore, use taobao direct better.

Here's one of the link.
https://item.taobao.com/item.htm?spm=a230r....bucket=5#detail

You get more choices if you fill in FnHon in their search option. Better still get someone who can write mandarin, you can communicate directly with the seller.