3 or 4 wheels

The short anwser:
If you are unsure about this, take 4 wheels.

The long answer:
Since about 2015 the market has been flooded with fancy 3 wheeled skates that look really fast, but do not be fooled by marketing. We like skaters to be as comfortable and secure one can be on their skates. The 3 wheeled skates usually stand allot taller and thus make every technique (like braking techniques) allot harder. You might win some small amount of speed with 3 big wheels, but the lack of confidence you will have on them will ironically maybe even make you go slower in the end because you will be more risk averse.

4 wheels also will give you better feeling with the road. The more points of contact you have the better the ride is when the road is kind of bumpy.

Wheel size
One of the main differences between three and four wheel inline skates is wheel size. Four wheel skates typically have smaller wheels, which means they are lower to the ground and offer more stability. On the other hand, three wheel skates have larger wheels, which allows for faster speeds but can also make them less stable.

Ride height
Another difference is the height of the skate. Four wheel skates are lower to the ground, which means they have a lower center of gravity and are less likely to tip over. Three wheel skates, on the other hand, are higher off the ground, which can make them more prone to tipping.

Balance
Balance is another key difference between three and four wheel skates. Four wheel skates have a more evenly distributed weight, which makes them more stable and easier to ride. Three wheel skates, on the other hand, have a more pronounced tipping point, which can make them more challenging to ride and less stable.

The amount of wheels
You would never take a 4 wheel skate, and take a wheel off, would you? This indicates any 3 wheel setup is a compromis. Four wheel skates have a more evenly distributed weight, which makes them more stable and easier to ride on rough or uneven surfaces. Three wheel skates, on the other hand, may get stuck more easily on rough surfaces due to their higher height and less evenly distributed weight.

Fewer wheels = less fun.

In conclusion, four wheel inline skates are generally considered more stable and easier to ride for beginners, while three wheel skates may be better suited for more experienced skaters who are looking for faster speeds and more advanced tricks. Ultimately, the choice between three and four wheels will depend on your personal preference and skill level.