Cross-posting, or asking on multiple SE sites, is generally discouraged. You should pick the most appropriate site and ask there. If little or no response, you could flag with a request that it be migrated to an alternative.
You can post a link to a question in another SE site within your question, but they don't show up in the Linked or Related sections on the right side. The question might appear in the Hot Network Questions section (the only way other communities will see it by default), but whether it gets noticed or not is another story.
If someone happens to follow both SEs, it's possible that they'll notice a question on one or the other. But for just regular/single SE users, no, they likely will not see a question posted to another SE.
This is discussed a few times on Meta SE. For example, How to ask the same question on different sites? which is now a duplicate of the more reviewed Is cross-posting a question on multiple Stack Exchange sites permitted if the question is on-topic for each site?