I have a query regarding the migration of SP2013 to SP2019 on-premise. I have gone through the Microsoft document and understood that we can migrate SP from SP2013->SP2016->SP2019.
I have doubts on content migration.
But , how the content will be moved to new environment? Even if we do database attach method, whether the Site Collections, sites, other custom solutions will be available in new SP2019?
So is it necessary to use a 3rd party tool like ShareGate and if we are using it, at what stage we need to start using it? Is it after the new SP2019 farm setup and database attach is completed?
Note: This is highly customised SharePoint.
Any suggestions is highly appreciated.