I thought in 2021 it was adopted that it was changed from 20 to 22
"Squad size increase. (1) Recommendation. That the squad size (i.e., players in uniform and eligible to compete) be increased from 20 to 22 with a corresponding increase to the travel party from 28 to 30. In addition, that teams be permitted to have up to an additional three student-athletes (for a total of 25) in uniform within the dugout limit. If teams use the full complement of 30 within the travel party, 22 of those individuals must be student-athletes eligible to compete. (2) Effective date. 2022 Championship. (3) Rationale. Reinforced by continual input from the NFCA over the last several years, an increase in the squad size from 20 to 22 will address significant participation growth in the sport. The growth is generated by both campus decisions to commit to larger roster sizes along with the increasing physical demands, especially for pitchers, which make it necessary for teams to increase their roster size. In the past, it was unusual for a team to have more than two pitchers; now most programs have three or more pitchers and are more likely to have specialization in position play, increasing the average squad size to over 20 (average is 21.9). As softball programs increase their rosters, the committee believes the championship squad size should also increase so that studentathletes who have been part of the squad all season may participate in the championship. Teams will still be allowed to bring up to 25 student-athletes to be within the dugout limit of 35. These additional up to three student-athletes will be allowed to be in uniform, but will not be eligible to enter the game and teams will have the ability to change the designated squad size (22) members from game to game even within the same regional, super regional or WCWS site.
Do you have a cite from the rules change other than this??