Great question
When the entropy is strong enough, patterns are not as important. You can have a predetermined pattern in 16-18 characters long passwords and it will be uncrackable if the passwords are randomly generated with strong entropy in mind, it would take hundreds/thousands of years to crack with current day technology.
We update our smart passwords recipe from time to time according to how well they're being accepted on most websites. Up until recently, it was around 20-21 characters long, and we've reduced it to comply with even more websites, when we can't read the specific requirements of the website, we fall back on our default which is now a 19 characters long password.
You are correct that patterns in passwords could weaken them, but that is only of they were not randomly generated, short and do not contain a mix of lowercase+uppercase+digits+symbols. For example, if you generate passwords that are 12 characters long and contain 4 lower case letters, 4 digits and 4 lower case letters, that would be considerably weaker due to it being shorter and with lesser entropy. You can strengthen Entropy by adding other types of characters (mix uppercase/lowercase, add symbols etc).
You can also find password strength calculators online and paste some of these smart passwords in it to see how the passwords perform there, just make sure not to use these passwords for real later on