The Asus you quoted seems like a very entry model for a very high price.
I would also not consider any laptop without USB-C power delivery support these days. Power delivery means you can potentially charge your laptop using a mobile power bank. Really convenient when doing long projects etc and you don't have access to a power supply nearby. Unfortunately, despite how aesthetic looking many of the Asus laptops are, none of their current laptops support USB Power Delivery.
Can consider some of Lenovo's ThinkPad options on their website now. AMD models are quite cheap right now and they have power delivery support on all ThinkPad devices
Alternatively, can consider the Acer Swift 3, which is an entry level model with lots of features. 1.2k and you get Thunderbolt 3 support, 1TB SSD and 8GB RAM. You also get the latest Wifi6 support which may come in useful if the laptop is meant to be used over the long term.
Can also look at the recent Dells which support Power Delivery. The Inspiron 7000 series seem quite good, it has a Full HD screen with 100% sRGB (meaning that the colours are better), thunderbolt 3 and 16gb ram. The LG older models are also currently clearing stock and you should be able to get a good price.
HP envy x360 (Ryzen processor) also quite a good option, it comes with pen support.
I recommend either Best Denki, courts or Harvey Norman. Compared to Challenger, usually, if it's an older model, you can try to negotiate with them for a better price (eg 150, 200 off). I will tell them, don't need to give me the free gifts, just give me a discount off the price. I also won't get their extended warranty.
Warranty wise, I think both Lenovo and Dell offer on-site warranty upgrade options on higher end models, with the possibility for accidental damage protection. This means, even if you drop the laptop and it spoils, or you spill coffee on your keyboard, you will be covered under warranty. I don't think the other brands offer this in Singapore right now.