Hi Michael,
The possibility of creating such a task depends on your exact needs.
Most subliminal priming tasks require very high control of stimulus presentation.
This type of control is not possible in web based platforms.
This limitation is not unique to Qualtrics or to MinnoJS, rather it is caused by web technology itself (namely, by browsers. see for example Bridges et al., 2020;
https://peerj.com/articles/9414/).
Assuming this is indeed your need, I would highly recommend that you stick to an offline platform (such as inquisit lab).
best,
Elad