I'll weigh in here, because I haven't had anything to do with the question so far. Others who were involved can give an answer if I've missed anything.
Your original question was tidied up with ten minutes, and it was
Difference between backwards, backward, and backwardly
What is the difference between "backwards"/"backward" and "backwardly"? They're all adverbs, but I feel like there's some sort of difference in their meanings and uses.
There is a minimum requirement of research, which you have attempted to meet by including links to a couple of dictionaries.
Unfortunately you haven't included the bits of the definition which might answer the question but don't, nor have you explained why the dictionary definitions are unhelpful to you.
You then added links to a similar question which does not mention backwardly: that's fine, you're asking about backwardly and that question doesn't help.
However, you then added
Since "backwards" and "backward" are the same and just different variants (UK and US, respectively), I mainly would like to know their difference with "backwardly", which is a word that I have never used, but apparently it is a word, according to Cambridge Dictionary.
OK, it's word which is defined by Cambridge. You need to add your research to the question and explain why it doesn't help. You should not expect others in the community to look up the definition and guess which part doesn't help. In fact the closure message has a link to a question about research which has a checklist upon which each point is expanded:
- State what you're asking about first
- Never just link. Always quote with attribution.
- Use simple language. Assume all your readers are from Missouri
So far, you have fallen foul of point 2. As that question says (edited for this context),
By doing this, you are showing that the meaning of backwardly isn't easily answered by referring to standard works. You have already done that search and you have shown what you found. You state how you have attempted to deal with what you found, and you explain what the problem is: you can't actually find a definition which appears to differentiate backwardly from other similar forms.
However, the reference to the "Show-Me State" is also relevant: you need to demonstrate that nothing you have found has helped.
In addition to all that, Laurel has commented "Why was this deleted off ELL and reposted here?" I can't see deleted questions on ELL, and I can't find an account for you there either; but it's bad form to re-post somewhere else questions which [almost certainly] had a bad reception on a site, especially if the question is not improved the second time round. You appear to have done this before, as I commented on another post, "This question would (in my view, and another moderator's) be better on English Language Learners, but they rejected it for lack of research, and three reviewers [on ELU] have voted to keep the question closed." You now have three negatively-scored questions, and risk triggering The Algorithm which restricts the ability to ask further questions without improving your existing posts.