“Better off” is great here. A few tips:

1. We say, “in my 60’s” to mean, between the ages of 60 and 69
2. You can say, ” …than I was when I was 30.”

So it can be: “I’m better off in my 60s, in middle age, than I was when I was 30, not materially or financially, but due to my mindset and expectations.”

Perfect!

perfect

perfect!

You are better off starting your day with healthy breakfast rather than skipping it.

Thank you, I get it.

This is almost right. I should have made this clearer in the discussion, but:

1. If you state a fact (that someone is better off), you would say, “Non-native English speakers are better off because they can understand complex topics easily.”
2. But if you are giving someone advice, and saying what they should do to improve their situations, you can say, “better off” plus an -ing verb: “You’re better off taking that new job” means, “You would be better off if you took that new job.”

Therefore, you can say:
1. Non-native speakers are better off because they have Plain English to help them understand more complex topics (a statement of fact)
2. Non-native speakers are better off subscribing to an online tool rather than trying to learn it all themselves (advice because it uses an -ing verb)