On the fatigue part. (Jokingly) It will not get better, you just get faster. With that out of my system, it will get easier and soon you will find yourself more energetic. Because extra training.

When it comes to safety you are going at it the right way. You look for back roads, slower roads, residental roads etc when there aren't cycling infrastructure. But uf it is unsafe I would think twice/thrice if it is worth the risk. Luckily it sounds motorists are already used to safely overtaking slower two-wheeled vehicles.

Depending on your cycling community you can have great use of cycling/outdoor apps with heatmaps. Then you can see where others are travelling. Strava, Ride with GPS and Komoot are useful for me locally. Especially strava with the large community.

On the topic of fatigue: They to eat enough. It sounds silly, but you burn quite some calories while riding a bike and you will need to fuel yourself. Have something with carbs after the ride or even a snack during. You will also get used to it more and more over time. The first rides are always the hardest.

And it might really not be possible in the place where you live, but prefer smaller paths/roads over the main roads. It might add a couple of km to your ride but you will reach your destination much more relaxed.

Wish you all the best.

In the US, many states have a law specifying a minimum passing distance when passing a bike and it is normally 3 ft (about 1M). I have seen some cyclists cut a very bright piece of foam (usually a pool noodle) and attach it to the back of their bike sticking out into traffic. This creates a visual barrier to encourage people to give more room when passing. I don't know how the laws or culture are in Malaysia, but maybe something like that would help.

Here's an example (from Canada): https://www.ctvnews.ca/canada/cyclists-in-toronto-riding-with-pool-noodles-to-protect-themselves-from-drivers-1.4082620

So how did you guys that do the commute able to keep going? Any advice on that end?

I rode further every time I went out, and it eventually got easy to get to distances that were previously "impossible" without stopping for a break. My first ride after not being on a bike for maybe 20 years was only a few KM, and that was incredibly difficult! Less than a month later, I was up to 100km. Last weekend, I rode 200km, came home, walked several more KM to pick up ingredients for dinner, came home, made dinner, and did 80 km the next day. LOL You just get more fit with time and riding.

I will say, though, that at a certain distance, you will want to consider a food/water strategy. I know that I can generally ride for about two hours without needing to snack, or even sip from my water bottle. But for hours on the saddle, I prepare with snack bars and water. I still suck when it comes to eating enough on really long rides, but that's more about training my stomach to get used to eating constantly (which I don't do off the bike).

Also, at longer distances, you'll want to consider making your bike as comfortable as possible. Make sure your saddle is the right height, that your handlebars are setup correctly, that your posture is good, etc.

Good luck!

Full time commuting is pretty dangerous. I've been riding bikes for years, and all of the issues I've run into over the years almost all came on commutes.

I just treat it as a special treat every now and then. If you do it everyday it gets old pretty quickly. I mean if you have a nice commute then maybe it's OK. I used to commute into downtown in a city where the war of Bikes vs Cars was very much alive though, and I just decided ultimately it wasn't worth it. I mostly just ride outside of times when everyone is overfilled with rage, and it's more enjoyable. Sucks it has to be that way :/