Search for a pattern spanning multiple lines between 2 strings and does not include a different string, then replace with new value

The title may be a bit vague, but I have a file that contains something like this

<Tag>
 <Tag 
    111
    222
 />
</Tag>

Using bash script (grep, sed, awk, etc.) I want to search for the inside tag and replace it with some new content

 <Tag>
     <Tag 
        333
        444
     />
    </Tag>

The new content can be all in one line, ie <Tag 333 444 />
I’m struggling with how to search for the inside Tag only, I can’t find a way to extract a string starting with <Tag and end with /> but doesn’t contain >. Any help would be appreciated.

>Solution :

If this, using GNU sed for -E and -z, isn’t all you need then edit your question to provide more truly representative sample input/output including cases you have that this doesn’t work for:

$ sed -Ez 's:<Tag[^<>]+/>:<Tag 333 444 />:' file
<Tag>
 <Tag 333 444 />
</Tag>