I tried to compare to date picker fields in contactform7:
FROM:

<input class="wpcf7-form-control wpcf7-date wpcf7-validates-as-required wpcf7-validates-as-date dateclass" id="dateanr" min="2024-06-11" aria-required="true" aria-invalid="false" placeholder="01.01.2024" value="" type="date" name="VON">

TO:

<input class="wpcf7-form-control wpcf7-date wpcf7-validates-as-required wpcf7-validates-as-date dateclass" id="dateabr" min="2024-06-12" aria-required="true" aria-invalid="false" placeholder="01.04.2024" value="" type="date" name="BIS">

My JQUERY look like that:

/* 
---Setzt das Abreisedatum automatisch auf Anreisedatum +1Tag ---
*/ 
jQuery(document).ready(function( $ ){
    
 jQuery(($) => {
    const dateStart = $('#dateanr')
    const dateEnd = $('#dateabr')
    const minBuffer = 1

    // Only allow dates in date end field that are after the date start field plus the minimum buffer
    dateEnd.on('change', () => {
      const startDate = dateStart.val()
      const endDate = dateEnd.val()
      if (startDate && endDate) {
        const startDateMoment = moment(startDate)
        const endDateMoment = moment(endDate)
        const minDate = startDateMoment.clone().add(minBuffer, 'days')
        if (endDateMoment.isBefore(minDate)) {
          dateEnd.val(minDate.format('YYYY-MM-DD'))
        alert("Abreisedatum muss nach Anreisedatum liegen!" )
        }
      }
    })
  })

This works fine in Chrome but not at all on firefox and MSEdge. Can anybody give me hint why?