Having full power for every team to modify their stuff in next-gen project has its pros.
But it also comes with huge cons if you try to manage a larger organization and you want to standardize a few things. It is the same nightmare as it is now with jira service desk: you need to manually copy all the stuff over and over and you can not do one change in one place - you need to do it everywhere.
I really don't see how this could work out well in the end - it is why we try to limit the use of Jira Service Desk and it has the same cause on jira next-gen projects.
I just googled around - is there any kind of strategy from atlassian if there will be possibilities to share configurations (e.g. issue types, workflows) and so on. basically the same question applies to JSD configs like automation rules - it is just so painfull to manually all this stuff by hand and that in the 21st century....