Can I customize SharePoint Modern Teams site global menu style?

Anyone got any easyish ideas for styling this global nav menu in a modern UI SharePoint Team site?
The text is so tiny these days, and the child site model works better for this team as all content is managed by the Learning&Development group.
(Big Global org, so no access to use PnP SPFx, and no chance to change tenancy settings. Need something we can do at a Site collection level really).
Google is not my friend today! Is there anything we can do?
Can this menu be formatted?