Addendum:

In Joomla 3 I realized this with a plug-in, which no longer works under Joomla 4: "System - Equalheights: Plugin for height adjustment of DOM objects with the help of Javascript, based on their CSS classes By Digital Disseny"

https://www.dropbox.com/s/vpl7zjz00brn4zj/chat3.JPG?dl=0

Hi,

1. It not our plugin, so we cannot help!
2. Easier would be to use custom CSS to set min height value for all objects "buttons" where you used class. One line is needed! Without using extra plugin.

.equalhigh {min-height: 75px;}

I guess it couldn't be easier. Are you agree with me?

After using it.

Und here is premium version of CSS code with align-content property that you can use instead:

.equalhigh {
  min-height: 75px;
  align-content: center;
  display: grid; }

After using it:

Hi Paul, unfortunately the solution only works until I change the width of the window. I experimented a lot. Unfortunately, your solution does not help me.