Vivaldi can learn a thing or two from Safari about being able to copy and paste a HTML table into a spreadsheet. Safari does quite well here:

Screenshot of Numbers for MacOS of a well-formatted paste of the AWS RDS DB instance details table copied from Safari

Vivaldi, not so much:

Screenshot of Numbers for MacOS of a badly-formatted paste of the AWS RDS DB instance details table copied from Vivaldi. Instead of the cells of a row from the original table being formatted as a row, each cell appears on a new row