Most of us have a bias towards our own machines, so it is going to be difficult for you to make a decision based on what we write about our machines. I am 80/85kg and the field that I generally use is at 300m
I have a Miniplane Top 80, it works for me because:
The geometry of the machine makes it a delight to fly, almost no torque steer
It’s one of the lightest. Which makes it easier for you on the ground and you are less likely to stumble if you are not struggling with a heavy machine.
It’s fuel efficient. Which means that you have to take up less fuel for a given length of flight, which means that it’s lighter still.
It’s relatively quiet. Which means you are less likely to disturb anybody, which is important.
It’s tried and tested. Probably one of the most sold motors in the world and has been out there for more than 10 years. You aren’t paying for the privilege of being somebody’s test pilot.
The parts are readily available and inexpensive.
There is a great informal network on the internet and it is easy and quick to find help on any aspect of the motor.
The compromise is that it is not as robust as some machines.
Generally speaking, go for the bigger brands until you know better, and avoid Dell. A big engine with more thrust might sound like a good idea, but it is probably not a blessing for a new pilot.