Lucene: fast(er) to get docs in bulk?

To fix this issue I am not sure what's the end goal of this activity, so pardon if the following solution doesn't meet your requirements.
First, if you want to delete documents, you can use IndexReader, which you have already created. IndexModifier is not required.

IndexReader[] readers = new IndexReader[size];
// Initialize readers
MultiReader multiReader = new MultiReader(readers);

IndexSearcher searcher = new IndexSearcher(multiReader);
Hits results = searcher.search(new TermQuery(t));
for (int i = 0; i < results.length(); i++) {
    int docID = results.id(i);
    multiReader.deleteDocument(docID);
}
multiReader.commit(); // Check if this throws an exception.
multiReader.close();
searcher.close();

Does that help The field must be indexed. If a field is not indexed, its terms will not show up in enumeration.

I wish this helpful for you This is a QueryParser configuration you have to adjust. Usually you have the option to allow leading wildcards for your QueryParser. As an example StandardQueryParser with method:

setAllowLeadingWildcard(true)

it should still fix some issue Index segment files in Lucene are immutable they never change once written. So when a deletion is recorded, the deleted record is not actually removed from the index files immediately, the record is simply marked as deleted. The record will eventually be removed from the index once that index segment is merged to produce a new segment. i.e. the deleted record won't be in the new segment that is the result of the merge.
Theoritically, once commit is called the deletion should be removed from the reader's view since you are getting the reader from the writer (i.e. it's a real time reader) This is documented here: