Since shower and toilet are part of the fuel station, then in theory simply tagging toilets=yes and shower=yes on station should suffice [1]. Those tags were among many others which were added in changeset 72405866 [2].

I've reached out some other mappers to consult with them on the matter, but they haven't responded yet. Also I'm not closing the note because apparently whatever would be decision, toilets and showers would similarly need to be tagged on CircleK's station in south as well [3].

[1] - https://wiki.openstreetmap.org/wiki/Tag:amenity%3Dfuel#Additional_services
[2] - https://osmlab.github.io/changeset-map/#72405866
[3] - https://www.circlek.ee/station/circle-k-m%C3%84rjamaa