There is no single answer that applies to every shop, because it depends on which IBM i release your applications currently run and the specific Power 10 or Power 11 machine type-model you are targeting. IBM sets a minimum supported IBM i release for each new Power generation and periodically stops shipping Technology Refreshes for older releases on the newest hardware, so a release that has run fine on Power 9 for years is not automatically guaranteed on newer hardware.
Before finalizing a migration plan, confirm three things: which IBM i release is currently running, whether that release is still inside its support window at all, and which releases IBM lists as supported for the target hardware. If the current release falls short, the OS upgrade needs to be sequenced into the migration plan alongside the hardware move, with its own testing checklist for exit programs, PTF levels, and third-party software compatibility.