how to replace get_template_part(‘loop’,’tag’) with explicit styled version?

I think you misunderstand the purpose of get_template_part(). It is a wrapper for locate_template(), which itself is just a wrapper for include().

By calling get_template_part( 'loop', 'tag' ), you are telling WordPress to look for/include a file based on the following priority:

1. Child Theme loop-tag.php
2. Parent Theme loop-tag.php
3. Child Theme loop.php
4. Parent Theme loop.php

If you need to modify the markup of the loop itself, then you simply need to modify the appropriate file, according to the above priority list – e.g. loop-tag.php in your Theme or Child Theme.

You may need to create this file; if so, copy loop.php, name the copy loop-tag.php, and edit as necessary.