The original hope was for it to be tied to the Olympics but it had problems even before the COVID hit.
The summer 2018 anime series Free! -Dive to the Future- brought out its compilation film back in 2019 and had set plans for an original film as part of summer 2020 previously that would tie nicely into the Olympics.
With both films out in Japan, the folks at Peppermint Anime in Germany have it coming as two separate releases on Blu-ray and DVD.
Free! the Final Stroke - the Second Volume - Trailer (DE)