I'm trying to systematize the use of 'the' with ranking adjectives like 'next', 'following', 'third', etc.

What I know, is:

usually ranking adjective are used with 'the'=>

I will pay the next time we have dinner.

Don't forget the following rule.

but at the same time=>

Maybe I can do that next summer.

We could get together next Monday.

I think I did well on the test, but I won't know until next week.

So, as I understand it:

Next+days of week,seasons and expression next week are just some exceptions I have encountered so far.

I want to know how it actually works. If I'm oversimplifying the matter or completely mistaken about it, that's alright, I just need to figure it out. Thank you.