Engineers App is "installer" only. Anyone can download the normal free apps even if you have a panel or not.
Other manufacturers have subscription models which need you to go through an installer.
Any maintained system will be more reliable than a non-maintained system, but that wasn't the original question.
I fully agree that a DIYer can spend weeks or months doing something that an installer can do in 1/2 day but clearly the OP has done this before so is willing to take a punt.