I must add the caveat that I don't know much about the top foreign managers, but, yeah, in trying to read up on all the suggested ones then I'd say Nagelsmann definitely seems my preference.
Also Xabi Alonso, but the Liverpool connection (and likely destination) makes that seem very unlikely.
I'm a bit worried that most of those available seem to be either young and up and coming, but no experience of top clubs or winning major trophies; Or they have the latter experience, but seem nowadays to mostly be on the merry-go-round of big clubs and getting sacked quite quickly rather than building any long term success anywhere.
Nagelsmann seems to be one of the few who falls somewhere in between - still young and up and coming, but already gained experience managing Bayern Munich and Germany, two high profile jobs. He'd also, presumably, be an easier and cheaper person to get as regards compensation as isn't his contact up at the end of Euro 2024?