This Power Automate Flow shows how to convert HTML tables into a machine-friendly format such as pipe-delimited file or csv. The delimiter character can easily be changed. I have presented the concept in a simple manual trigger on a hard-coded Html content (which itself doesn't contain standard HTML - just to show how bad it can get). This flow can be extended further to get the Html file content from SharePoint, OneDrive or Email content. The idea was to keep things simple so everyone can understand.
The trick is to only use 'Html to text' action to remove all the Html in order to avoid heavy parsing of the string.
The output file content can be viewed in a table by going to CSV Viewer (if you want to validate it).