I've had this same question in my head for a while. I think many people consider it given the success new school players are having against the field in general. Alot of the materials that are available today and sometimes on this thread (given that many of the "essential" or "official" threads on here are 10 years old) can be difficult to utilize. These resources have valuable information, but it is hard to know what is relevant anymore when trying to learn the game. Many younger players have great resources that some of the old school guys never had (Twitch and Youtube) are awesome tools to have. It certainly feels hard to determine what the most advanced players today (spreadsheets and solvers and god knows what else) are using to become advanced players.
A number of players like Matt Berkey and Daniel Negraneu (among others) have talked about how the styles of players like Fedor Holz and Dimitri Urbanovich may only be successful within a certain window. These players believe that once people get to understand your game they can exploit it even if you play close to GTO (like many new age players attempt to do). Old school players believe this because they've seen the game change on them and they've had to adjust. New school players think that GTO is the closest NLHE can ever get to being "solved" and they'll never be beaten by the old school guys. They're probably both wrong and computers will turn into robots who rule the universe, take dominion over mankind and solve all poker variants (
https://www.cmu.edu/news/stories/arc...er-player.html).
As someone who loves chess, I think it is an incredibly challenging game, but it is fortunate that the resources available to learn the game never become outdated. Openings invented centuries ago are still applicable today (
https://en.wikipedia.org/wiki/Ponziani_Opening). I think if you read every resource from 1978-2000 like the Bible tomorrow, played that style for 20 years in a vacuum, and then got transported magically into next years SHRB you would get decimated by the field. (Please don't tell Mason Malmuth about this wildly impossible hypothetical scenario).
Ultimately, I don't know what to tell you because I don't think anyone really knows what Fedor is doing RN. I believe the fundamentals of his success are firmly grounded in a mastery of the mathematics of the game, and adjustments that he makes to the field to play optimally against them. To get to that level at 23 is some wizardry tho.