Well, the article speaks of "Deutsche Bank strategists" and "experts", and it is Deutsche Bank Research that made the suggestion. Digging further, the person who made the suggestion is a "Macro Strategist" doing "Macro Research", certainly not just a junior.
https://www.dbresearch.com/PROD/RPS_EN-PROD/PROD000000000051...
there are countless articles to be found about this if you just look for anything like "working from home tax deutsche bank", for example:
https://www.dw.com/en/deutsche-bank-proposal-to-levy-income-...
https://www.cnbc.com/2020/11/12/deutsche-bank-proposes-a-5pe...