change default /blog slug in multi-site main blog

This was addressed before, but there was no satisfactory answer.

I went into the network admin dashboard and changed the Permalink Structure from /blog/%postname%/ to /main/%postname%/

I saved this, and cleared the browser cache. Now all the posts follow this permalink structure: https://www.mydomain.com/main/postname if I copied and pasted this into the URL bar, I get the page.

However, from the homepage, clicking on the title of the posts links me to https://www.mydomain.com/blog/main/postname and when I go into the mydomain dashboard (not the network admin dashboard) tools>settings>Permalinks, I see that wordpress does not change /blog to /main. Instead, it automatically selects ‘Custom Structure’ and enforces /blog/main/postname

I am going to stick with /blog for now, but if anyone has a fix…