The thing with Gamestat is that it's all estimates and it's not really accurate and has huge margin of errors, especially for anything prior to 2018 when the PSN trophy hack happened, since the site was created after that happened so anything prior to that 2018 date has even more inaccurate and incomplete data, and is unreliable. It can be helpful for rough ballpark basic idea kinda thing but when getting into specific numbers it doesn't really hold up.
Gamestat only uses trophy data obtained from 8 million PSN accounts, it then extrapolates that by artificially inflating the numbers, so it doesn't have data tracking the 100m+ PSN accounts either.
For example Atlus announced vanilla Persona 5 had sold 3.2 million in December 2019 but Gamestat says it has 3.6m players in December 2019, inflating it by 400k.
Currently gamestat says vanilla Persona 5 is at 4.3m players, even though Atlus says that the combined sales of Persona 5 and Persona 5 Royal is 4.6m, with P5R doing 1.4m by July 2020, meaning vanilla P5 is still 3.2m.
So in December 2019 Atlus said vanilla P5 was 3.2m and that Persona series sold 11.1m, and then in July 2020 they said P5R sold 1.4m and that P4 on Steam did 500k, and that Persona series now has sold 13m, so the 1.4m of P5R and 500k from P4 Steam added to 11.1m give us accurate display of actual official sales for Persona 5, which gives us proof that vanilla P5 has still sold 3.2m by current 2020 date which compared to what Gamestat says has a margin of error by inflating P5's players by 1.1 million above what its actual sales are.
http://p-ch.jp/news/5850/
http://p-ch.jp/news/4855/
So like how FF7R had "4.2m players" according to gamestat since mid July, that too would be an inflated sum above what its actual sales were at the time. The FY2021 1st quarter SE total sales (shipment+digital sales) were 6.21m, of that number there was 5m shipment+digital of FF7R, and the rest of the 1.21m~ was Trials of Mana and whatever else games that sold that it is accounting for.
The whole quarter has 56% digital sales distribution of that 6.21m, and with Matsuda's statement 2 weeks ago about 50% of 7R being digital and it implying 7R had 4m sell though, it's possibly even higher than 50% for 7R's digital sales.
According to gamestat 7R had "4.2m players" by mid July 2020, which is already higher than what the latest sales chart would imply its actual sell through is by at least 200k