Consider a website (example.com) is ranking in top 5 for keyword :
get rid of fruit flies. with a guide and a list of best products for this issue.
Another website, with lower DA, yet strong enough authority on the same topic, is also ranking for the same keyword on first page, with a guide on how to get rid of fruit flies.
The owner of the first website offers to buy the article from the second website and redirect it to his own landing page to consolidate his position on the SERP.
Could this be considered illegal or penalized by Google guidelines?
There are many site owners that buy domains and redirect them to gain some keywords or domain authority. But, this situation is about redirecting some articles from various blogs that are ranking well enough for the same targeted keywords.
Note: examples are pure fictive to illustrate a general situation [edited by: not2easy at 4:14 am (utc) on Feb 15, 2022]
[edit reason] please use example.com for examples [/edit]