The problem with these tools is that they have to check every single keyword before having a full report. This is why I would never trust a single tool when doing keyword analysis, specially when comparing competitors sites. In this case, if you check Ahrefs you will find they have a good amount of potential traffic with a ton of keywords ranking just for that page (1K+)
You have to understand how these tools work: they use the same type of spiders that Google use, and they keep crawling and crawling the SERPs with tons of different keywords, putting down the total volume for each keyword (using probably Google Ads volume API, and also the information that comes from thousands of users that have shared their GSC control). Then they pick the top 100 results per each keyword searched, and assign a number of potential visits per position. So if it has 1000 potential visits, they may assign 400 visits for first position, 200 visits for second position etc, and then they sum up all this information, and you get the potential result
The problem is that they should be informed of each single keyword that can potentially rank for this page. So in the case of this one check that Ahrefs have found a ton of keywords while Semrush have not found none at all.
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