Hi ilias_;
Thank you for contacting us.
Regarding the removal of the tag (oneway=yes)
According to the OSM wiki https://wiki.openstreetmap.org/wiki/Tag:junction=roundabout#:~:text=oneway%3Dyes%20is%20implied%20and%20redundant.%20In%20specific%20cases%2C%20it%20can%20be%20added%20for%20clarity%20though
(oneway=yes) is implied and redundant. In specific cases, it can be added for clarity.
Best regards,
Aya Samir