I'm sorry to sound "pesimistic": There is nothing that can be done in the short term to prevent that certain type of users post blatantly off-topic questions on SE sites.
It looks that somehow certain type of users find the "Ask question" button and just start typing on the editable boxes ignoring any guidance provided in Ask question form other than the messages alerting them why the question cant' be posted.
On Web Applications, I'm one of top ranked users there, there is a similar problem, there are a lot of questions about developing web applications, code only, complains, customer care / client service, recommendations questions. These kind of questions are off-topic as Web Applications is it focused only on using specific web applications.
As this site, Web Applications, have community-specific close reasons that have being adapted from time to time to the most frequent tendencies of blatantly off-topic questions.
P.S.
- So far on Web Applications we only have received two questions about ChatGPT, one about troubleshooing and another about installing code found in GitHub. Both type of questions are off-topic.
- On other sites the term "spam" is used for posts blatantly promoting external content. Other undesired posts are just called "off-topic" even those that only include a selfie.