The rule is meant for all playable league (on FM23) and the cup in Norway. The main document for all rules in Norwegian football was released in January, and has not been updated. So the rules for 2023 will probably be released ( @ www.fotball.no ) in January 2023. The only confirmation I can find online is through Eurosport ( link: https://www.eurosport.no/fotball/fem-innbyttere-i-toppfotballen-innfores-permanent_sto8990886/story.shtml )
This story confirmes that the temporary covid-rule is made permanently.
Regards
Mats