Is the _IBRD marker too crowded?
It could become (with line breaks removed):
<svg width='10' height='10' viewBox='-400 -400 800 800' id='_IBRD' xmlns='http://www.w3.org/2000/svg'>
<circle r='400'/><circle fill='#FFF' r='358'/>
<path d='M-21 -378H21V378H-21Z M-378 -21H378V21H-378Z'/>
</svg>
Old and proposed:

