Use of present tense in a subordinate clause within a sentence that uses future tense

Is the use of tenses correct in the following sentence ?

"One of the key components will be the XXX that replaces the existing YYY."

In particular, the use of the present tense in the subordinate clause whereas the main clause uses the future. It seems correct to me because the present expresses something that is true already now.

Solution 1:

Yes, it's fine.

The XXX that replaces the existing YYY is a noun phrase. You can consider it as a black box being placed into the surrounding sentence.

One of the key components will be [something].

Consider an actual sentence rather than just the variables:

One of the fruits on display will be the Gala apple.

You can add adjectival information to the noun:

One of the fruits on display will be the Gala apple [that won first prize at the harvest competition].

Returning to your original sentence:

One of the key components will be XXX [that replaces the existing YYY].

The only thing that makes this look strange is the use of the variables. Here is a more exact sentence that uses an actual example:

One of the new technologies on display will be the Wonder Car [that replaces the existing types of gasoline with white bread for its fuel].