Dude really? I'm trying not to be rude but re-read that sentence. If something has no limit. Another thing cannot have less of a limit...you can't have less nothing than nothing.

If I have one banana, and you take my banana. I have no bananas. Having negative bananas is impossible since there are none left.

Replace the word banana with limits. Presto. Just like you can't have more infinity than infinity.

Infinite × infinite. Still infinite. It isn't a number it's a concept of a limitless amount of something. Infinite minus infinite. Still infinite.

There are two types of infinite yes, but one is not more than the other. There is countable infinite. I.e. all the whole numbers.

And uncountable infinite. Say all the numbers between 1 and 2. This is only uncountable because there is no definite easily defined starting point. Both are a limitless amount. However one can be placed on a 1:1 scale with other items that's the difference it isn't in amount.

If a character has an infinite amount of power (omnipotent is the literal translation of this) it can't be one upped by any other character. True, 100% limitless power cannot be beaten only stalemated by a character who also has infinite power.