How about the GSC & Analytics (if any) traffic?
Ahrefs does not provide up-to-date or accurate analytics, sometimes it takes weeks for them to update some keywords/SERPs data,
How about the ranking positions for top/most of the keywords?
Penalized websites will usually get out of the SERPs for all/majority of the keywords, is it the case for you?
As per the screenshot, the traffic is declining, it's not totally vanishing, so probably negatively impacted & devaluated rather than penalized,
The website could be hit directly by the recent update for whatever reason, or indirectly in case any/many of the websites linking to yours got hit