There is no single right answer for modernizing PowerBuilder. Here is what the realistic paths actually look like, and what matters most when choosing between them.
DataWindow, PowerBuilder's core productivity feature, is also its biggest modernization obstacle: it treats a database result set almost like a first-class UI object, and that abstraction has no direct equivalent in most modern frameworks. Appeon, which now owns PowerBuilder's development, sells tooling aimed at modernizing the application's UI and deployment model without a full rewrite, which is worth evaluating before assuming a full migration is necessary.
Keep the code, modernize around it
Vendors taking this approach for PowerBuilder: Appeon.
Rewrite or convert to a new platform
Vendors taking this approach for PowerBuilder: AWS Mainframe Modernization (Blu Age), Accenture, 10decoders.
Fill the workforce gap without a migration project
Vendors taking this approach for PowerBuilder: Optisol.