I've already bought sesame and all it's pay walls specifically because of Nova. I actually bought sesame at the first Nova integration and have found it very disappointing I'm pretty damn bitter at them actually because after promising to support various apps for shortcuts on my first review they still haven't about 3 years later on fact they've took away working features to charge for them a second time.
I'm still happy enough with Nova I've tried various launchers but it's still the best but mentioning search and nova together triggers me due to sesame and their outright lies and double charging.
I still use sesame. Tasker is set as assistant app and it will launch sesame when assistant is triggered. It has served me well, but integrations are breaking so will have to see how long it will last. I also have Nova Prime but switched after the buyout.
Sesame was also bought out by the same company, so Nova and Sesame developers are working together with Branch.
Sesame basically stopped updating their app even before they got acquired, so they hadn't added any analytics or trackers. There were some updates after but they were just bug fixes. Exodus tells me there are no known trackers, I also haven't seen any suspicious traffic from it yet so I still use them.
Nova, however will be integrated with Branch and will likely phoning home.