Edit inside an HTML tag with ed(1)

Consider my humble _hello.html_ file, edited with mighty ed:

$ ed hello.html 
28
,p
Hello world!

What's your general approach to edit inside that *title* HTML tag (bonus if you can edit inside any HTML tag)? I tried a regular expression that matches inside the tag:

s/>.*/>My new title/p
My new title
u
.
Hello world!

But, sadly, you can see that I chopped my tag (and it would be way too much work to type out that _``_ bit every time!). For further education, I browsed through Software Tools in Pascal page to 174—see https://archive.org/details/softwaretoolsinp00kern/page/174/mode/1up?view=theater page—and discovered the _&_ special character that helpfully reaches the _middle_ of the sentence:

s/world/& again/p
Hello world again!

But, that's not quite right, since I want to substitute the middle, not just reach the middle.