My macro bar is also quite crowded and I too have problems scrolling it up and down. I've use the Stylus browser add-on with the following script to reduce the size of the buttons so they all fit on my screen without scrolling:

/*macro quickbar */
#macrobar {
height: 4.0em !important;
width: 92% !important;
background-color: rgba(0, 0, 0, 0.44) !important;
text-align: left !important;
margin-left: 0px !important;
}
div.macrobox button.btn {
padding: 0 4px 0 4px;
font-size: 0.8rem;
line-height: 1.0rem;
margin: 0px 0 2px 0;
}
#macrobar_macros {
white-space: normal !important;
margin-left: 1% !important;
margin-right: 1% !important;
padding-bottom: 0px !important;
}
#macrobar .macrobox {
margin: 1px 5px 1px 5px ;
}
#macrobar div.macrobox:hover, #macrobar div.macrobox.ui-sortable-helper {
padding-right: 12px;
margin-right: -7px;
border-radius: 3px;
background-color: #999;
cursor: move;
}
/* ==UserStyle==
@name app.roll20.net/editor/ - Mar 2024
@namespace github.com/openstyles/stylus
@version 1.0.0
@description A new userstyle
@author Me
==/UserStyle== */
@-moz-document url-prefix("https://app.roll20.net/editor/") {
/* Insert code here... */
}