Today, TSOs publish the "Bidding Zone Study Report" that most notably discusses if the DE (and the FR) wholesale elec markets should be allowed to have different prices in different regions.
My 2p arguing that this would be good for the internal market:
https://www.wirtschaftsdienst.eu/inhalt/jahr/2024/heft/8/beitrag/strommarkt-einheitliche-gebotszone-aufteilen.html