Hi Evo_2020 ,
Thank you very much for your post.
Not sure I understand the first part of your question, as you can manage stock any way you like. From stock central as well as from the WC product page. If there is a specific button or action you are asking about, pls, review the documentation on this forum or the WC documentation.
Regarding the 3rd party plugin, I am not sure, if it will work as we did not test it. As of Xero, again, not sure how you made the connection so can’t say if it will work.
Pavel