[Dropped] Unable to open XLS and DOC files

[carman]

Edit: Split from [Dropped] Unable to open XLS and DOC files because it is not your topic and if you have a problem you need your own. You have no idea whether your situation is the same, even if the symptoms seem similar. Please do not post in another's topic unless you are helping to solve their problem for them.

Same problem here. For no reason the data is lost in a file being used since 2015 and always saved in xls format. The data must be there because the file size is still the same. Being a rain chart it was used on regular basis. Is there a way to recover years of work? I have seen the "moral of the story", but that does not solve the problem.
OS is Catalina 10.15.7 and the OpenOffice 4.1.2.

[Zizi64]

Can you upload/share a sample file here?

[carman]

file is too big (979kB)

[Zizi64]

You can share the large files on a free file sharing service like the Google Drive or others.