This video demonstrates some aspects of importing and exporting templates.
If you create your own templates then you can back them up by exporting them to a file, that can later be imported back into a different Zabbix server.
Also, rather than creating your own templates, you can try and search the internet for something already created by somebody else.
The most famous source of user generated Zabbix templates is Zabbix Share. More recently, you will find many on GitHub, GitLab or other public code repositories.
Not all templates will work with all versions of Zabbix. You can only try, or attempt to fix the problems yourself, or maybe there is a way to ask the author of the template for some help.
Many templates are open source and licensed without any guarantees or warranty, e.g., MIT, GPL, Apache 2.0.