As you said, shapes don't work well in chases (I experienced weird shape movements where the fixtures do other movements than programmed before), I started with Cue lists but with chases I could control (on/off) the shape as I wanted.
Let's explain:
The shape would continue to run if you stopped a chase step in the same way
-> I encoutered a different result
The Chase was linked to a virtual fader. When I fire the fader from the chase, the chase started and the shape/movement begun. The SWOP button became lid and also the name 'Shape bla bla bla' above the fader became illuminated.
When I pulled back the fader down, the shape/movement stoped and both the SWOP button and name aren't longer illuminated.
So far everything was fine, except, the fact that the shapes/movements are strange/incorrect.
While using Cue lists I cannot stop the shape/movement in an easy way.
I investigated your 3 proposes:
1/
Cue list with 2 cues (on/off) - The cue list will contain many cues (different chapes) so this will not be an option
2/
Block shape - Tried this and this indeed stops shape/movement, however while this 'block shape' cue is enabled, I cannot run a chase where I used pan/tilt positions (I avoid shapes, because they seem not to work well in chases).
The chase runs once and then the scanners stop moving
3/
Speed Master - Assigned speed master. In this case the problem is that the cue list remains running on the background, even if the speed is set to 0. The result is that every cue, the scanners change there position. There is indeed no movement during the cue but when changing from cue to cue, in the cuelist, the pan/tilt position changes so there is a movement
Maybe it's helpful to explain what I try to achieve

Among others, I have 4 RGB PAR leds and 4 scanners
For the 4 RGB PAR leds I want to 'simulate' an 'old fashined controller' where you have a background fader, a chasing (animation) level fader, speed control, and so on...
The 4 scanners may work most of the time let's say on 'autopilot' (but controlled by Titan One, not autopilot mode from the scanner itself) but when there is a romantic moment

they have to play another animation (example: color red, slow motions, etc.), in this mode the 4 RGB PAR leds may produce a fixed color.
In summary I want to have 2 'modes'
Mode 1: Normal mode:
RGB leds have chases and different colors running automatically. I achieved this by creating:
- A virtual fader with only the Intensity channel recorded
- A virtual fader with a programmed Chase where I change the dimmer channel of the fixture and create in this way a Chasing animation. The chase has many cues so it's not boring, that's fine.
- A virtual fader with a programmed Chase where a color change is programmed. Also many cues to make it colorfull and have many variations
So far I controlled the scanners a bit in the same way with different virtual faders to control background intensity, chase intensity, color change and last but not least a chase with shapes for the movements but this became a problem becauce shapes don't work well in chases...
Mode 2: 'Romantic time'
I created a chase with only 2 cues where:
CUE 1: RGB PAR leds set to red and scanners to blue with a slow shape movement.
CUE 2: RGB PAR leds set to blue and scanners to red with a slow shape movement.
As shapes do not work well in chases, I changed to cue list but this has other consequences.
My Titan One knowledge is very limited I don't know how to program this in the best and easiest way.