I won't claim to be an authority on this. However, I work out at home and have my own experiences. That said...
I have a treadmill in my house and have been using it daily but kinda getting bored with it and feel like there should be more that I have to do.
If you find the treadmill boring, you have options. Yes, you could go to the gym. That's a fine choice. However, you can also do calisthenics, get a jump rope, make any of the DIY stuff Ross has on his site, or get some cheap weights from some place like Play It Again. For me, I just built a home gym over time. I don't mind the gym, but the main advantages of the gym are the equipment, the environment, and any motivators said environment may have. So it depends what you want to do and what your goals are. Speaking of which...
I’m still kinda new with fitness but basically, my goal is just burning fat, and the result is not satisfying, It’s already a month since I started using it but only lost 1kg so far. Should I just go to the gym?
If it's just
burning fat, diet will have more to do with that. So what are your goals once you've leaned out? What is the end point you're looking for?
From there, you can do a lot. You could do the typical 1/2 hour to hour long jog, you could do intervals on the treadmill, do more HIIT-type interval training, burpees, jump rope, something from one of Ross' books (they are excellent, by the way), or one of the countless options out there. so I think it pays to have a more measurable outcome than "basically, my goal is just burning fat." That's not a slam, but it's a bit ambiguous.
That's my $0.02 worth. Regardless of whether you go to the gym or not, you can still do a lot with little-to-no equipment at home or anywhere else that will keep you engaged and not bored and dissatisfied. If the results are not what you're looking for, you can tweak things.