On the surface, it might not sound like a single large template consisting of all resources will have problems, but there are issues that could arise in the future. Let's understand the issues that might come up with single large templates.
Problems with the single template
Reduces flexibility in changing templates
Using a single large template with all resources makes it difficult to change it in future. With all dependencies, parameters, and variables in a single template, changing the template can take a considerable amount of time compared to smaller templates. The change could have an impact on other sections of the template, which might go unnoticed, as well as introducing bugs.