We had a rough time navigating at low speeds with my Yamaha sx195 when I was going through no wake zones, under bridges, and near the dock is stressful
Coming from prop boats to the jetboat I was a bit concerned, but since there is no dog gear to deal with, going from fwd to rev or neutral is fast and easy. After just a few minutes of practice, I can dock better with the jetboat than I could with the prop boats. Note that if you're not experienced, single engine boats will always "wander" when going forward at slow speeds. This is normal behaviour caused by the prop/jet wash behind the boat which is roatating in the water. It causes the stern to push left/right left/right which pushes the bow back and forth. Don't try to compensate for wander, just keep the bow pointed in the right direction (twin engine boats don't really wander as the two thrusts counter each other).
Three things to remember for docking and slow speed maneuvering:
1 - you need thrust to steer easily so don't rely on neutral to coast, use the fwd/rev more and use TDE to keep fwd thrust to a minimum
2 - if you need more response, use No Wake Mode 1 or 2 (I use just 1) to get more thrust and TDE to keep fwd speed managable
3 - when you need rev you have to double the thrust level to get the same reaction as fwd because the impeller is still sucking in water and pushing it out the back and using a bucket to change the jet direction, so if you need to slow or stop, give it more throttle to get the reaction you need.
If there's any wind or current, I like docking at an angle - approach with the bow aimed in the middle of the dock area you want, then about 5 feet away turn the wheel to steer parallel, go to rev and at the same time turn the wheel toward the dock and the boat will slow and the stern will get pulled in toward the dock. Done right you look like a pro and stop perfectly parallel to the dock. My wife loves it when I do that, and she just reaches out and grabs the dock cleat with the dock line. Done.
As mentioned, practice helps - go into a quiet cove and practice docking with an imaginary dock or even use a float to approach and "dock". You should also practice backing up and turning to help retrieval of dropped items or people in the water so you come up to them without hitting them. We regularly use a boat-hook to retrieve garbage from the water like floating cans, bottles, hats, etc. Sucking them into the jet intake can ruin your day. Same with ropes, don't drive over one with the engine running or you can suck it up and wrap it around your impreller shaft.
Also note that we never added aftermarket steering fins - our boat is stock and the articulating keel (rudder) does a decent job for us. Ok the only addon I bought was a second "rudder" tie-rod shaft to balance out the steering control wear and improve the feel, but that doesn't affect the basics of how well it works.