You can't wear mixed fabrics. But you have to.

To be fair, I couldn't find a verse in Exodus 28 that mentioned fabric made of linen and wool mixed together

https://www.biblegateway.com/passage/?search=Exodus%2028&version=NIV

There are specific instructions to make clothing from a mix of different materials, the details for each piece are their own verses.

Like verse 6 “Make the ephod of gold, and of blue, purple and scarlet yarn, and of finely twisted linen..." and verse 15 “Fashion a breastpiece for making decisions—the work of skilled hands. Make it like the ephod: of gold, and of blue, purple and scarlet yarn, and of finely twisted linen."

Direct commands to make a fabric from 2 different materials.

Not sure if yarn and linen are two different fabrics

Yes, they are. Linen is made from the flax plant. Yarn is a word in English that has a broad meaning, it is a long continuous fibers that are interlocked.

But in the Hebrew the word means wool. Which wool is a type of yarn.

And this isn't me choosing to interpret that to mean wool. You can see the usage in the direct translations of the Hebrew bible (the old testiment) into English. They use wool where most Christian bibles put in yarn.

https://www.chabad.org/library/bible_cdo/aid/9889/jewish/Chapter-28.htm

These are direct contradictions to the earlier commandment to not wear mixed fabrics.

Apologists ignore the fact that every translation is an interpretation ... and they tend to interpret everything in light of their bias.