The TokuDB storage engine has been deprecated by upstream:
TokuDB is deprecated in the 8.0 series and will be supported through the 8.0 series until further notice. This storage engine will not be included in the next major release of Percona Server for MySQL. We recommend MyRocks as a long-term migration path.
Because MariaDB Server includes MyRocks as well, it makes sense to remove TokuDB in favor of MyRocks.