Removing H2 format from blog summary block

You can do like this, insert the snippet into Settings->Design->Custom CSS

.sqs-block-summary-v2 .summary-excerpt h1,
.sqs-block-summary-v2 .summary-excerpt h2, 
.sqs-block-summary-v2 .summary-excerpt h3 {
  margin-bottom: 5px !important;
  margin-top: 0 !important;
  font-size: 14px;
  line-height: 1.4em;
  margin: 0 0 10px 0;
  text-align: left;
}

This was perfect @bangank36, thank you so much for your help!