Looking on Google I find many documents talking about best practices and improving performance of Ionic PWA solution, but at the same time I see that some documents are divergent.
Considering the experience of the majority, can you indicate sites that explain about good practices and performance?
I am working with Ionic 5.4.16 and Angular CLI: 10.2.0 / Angular: 10.0.2
“Improving performance” is so vague that any answer you’ll get is likely to be useless. Before anything else, you need to profile the code and figure out exactly what aspect of the app is being unacceptably slow. You’ll get better advice if you explain what your app does and what’s slow about it, in as much detail as you can.
dear @rapropos my application is a system that manages service channels in small businesses and notification via WhatsApp and SMS to customers, I am in an initial stage with tests and validation. As it is the first software I develop, I have researched a lot about good development practices and how to analyze if the performance is going the right way.
If you have tips or sites that show me how to analyze performance and best practices, I really appreciate it.
That doesn’t sound particularly demanding in terms of performance; more so in terms of breadth of functionality. So unless you are directly encountering a situation in which the app is behaving consistently sluggish and unresponsive, I would concentrate my effort on making the broad feature set accessible and easy to use, having a consistent interface.
During testing I have not received any complaints about speed or crashes. I believe my concern is related to not having these issues in the future and so start checking now 
Thanks… I will continue working on the direction that you said.