Search file with *filename* python 3.8

[snippsat]

but not for files that have bestfile in middle of the name.

How or better what to adjust to archieve this then

As i mention you can adjust regex for all kind of matches,maybe you should practice a little on regex.
Here a link to regex 101 which is a fine tool for testing/learning.
Now it match all bestfile no matter whats's before or behind.