Test Optional

That depends on the school. Look up its common data set, if they have one from the last application cycle or the one before that, it should accurately represent the test scores they accept. There will usually be a table that shows different percentiles for admitted scores and if yours falls below the 50th percentile, it is below average for that school and you probably shouldn't submit it.

Going test optional can hurt your chances but it is better than sending in a poor score. If the rest of your application is strong, you will hopefully still stand a chance.