Marin Alsop and Naxos have come out with the second volume of the Schumann Symphonies (3&4), performed in Vienna's Konzerthaus with the Vienna Radio Orchestra (ORF). I listened to the "Rhenish" last night on Spotify (#3), and it was superb. I think it's a tad 'beefier' and peppy than Chailly's very fine rendition with the Leipzig Gewandhaus Orch. (Decca). I'll listen to the fourth symphony tonight. . . . . . . I don't think there's a huge different between Schumann's own orchestrations and Mahler's 'retuschen'. They just sound a bit bigger and more filled out with the Mahler score.
https://www.jpc.de/jpcng/classic/detail/-/art/sinfonien-3-4/hnum/11107667