It seems the best way to convert .topx files to .brpx files used in e-Sword bible study software is to use the eSword 9 converter specially designed for batch conversion of bible files. But you can do it with one by one basis in the original e-Sword software.
Convert e-Sword topic note to e-Sword bible reading plan.
We found 2 software records in the database related to .topx to .brpx file format conversion.
Microsoft Windows software - convert topx to brpx on Windows
A bible study computer software
Convert from topx file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned topx to brpx. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A dedicated eSword converter