If you use broad match keywords and have low impression share, you may want to review your exact match impression share data to see how your keywords perform on only those searches that exactly match your keywords.
Exact match impression share is a percentage calculated by dividing the number of impressions that your campaign received for searches that exactly matched your keyword by the total estimated number of exact match impressions you were eligible to receive.
Learn more about exact match impression share in the Google Ads Help Centre.