Convert Excel 2010 VBA Macro to be Compatible with Office 365

Hi have a multitude of Excel macros that worked perfectly in Excel 2010. However, when I upgraded to Office 365 (now Microsoft 365), my macros take a very long time to run, and Excel becomes unresponsive several times in the process. Is there an easy fix for this in Microsoft 365? Please help if you can. I am so stressed out!