For a complete set Blomstedt with the Gewandhaus, in my opinion, takes some beating (but is not on Qobuz, and the big white box of SACDs that I have seems to be deleted - label was Querstand). His 3-movement 9th with the Gustav Mahler Jugendorchester at the 2010 Proms, heard from the choir seats, was one of the finest concerts I have ever attended and is on Youtube.
Apart from that... each symphony seems to me to fare best in the hands of a different conductor - or conductors. Bruckner, more than most symphonists, can cope with very different approaches and still make sense. My favourites (I don't believe in "best"; dates given are recording dates, not necessarily the year of issue):
00,1,0 ...don't know (I haven't heard enough different recordings)
2 Dausgaard, Swedish Chamber Orchestra - on Qobuz
3 (1877 version, the one that makes sense) Haitink, VPO 1988 - on Qobuz
4 Jochum, BPO 1965 - on Qobuz
5 Furtwangler, BPO 1942 - the story of this recording is fascinating and the Testament remastering sounds astonishingly good, but be aware that it has been "corrected" to A440 pitch, which did not apply in Berlin in 1942 and which has slightly altered the tempi; the performance was likely to have been at ~A445 (so I've un-corrected it with Audacity); the DGG (Furtwangler Wartime Recordings Vol.9) and Russian Disc remasterings are on Qobuz
also Venzago, Tapiola Sinfonietta 2014 - on Qobuz
6 Dausgaard, Bergen PO 2020; Norrington, RSO Stuttgart 2007 (51 minutes), Solti, CSO 1979 (61 minutes)
7 no favourite
8 Karajan, VPO 1988; Barbirolli, Hallé 1970 (BBC Legends) - I can find neither of these on Qobuz, astonishingly in the case of the Karajan
and Furtwangler, BPO 15/3/1949 (rather than 14/3/1949) - complete with bronchial audience... but among Furtwangler recordings, this is the one for me; it's riveting (the Audite label has the best remastering, but the Music and Arts one on Qobuz is OK - monochrome cover, release date of 1 April 2011 identifies it)
9 ...depends whether you want the completion (I usually do) ...and if so, which completion (only Carragan gets it musically right - SPCM are just musicologists) ...and having established that, which version of which completion: Carragan 1983 was in my opinion never improved upon, and there is only one recording: Talmi, Olso PO 1985
without the completion, Blomstedt as above via Youtube, or Jochum, Bavarian RSO 1984 is on Qobuz in the complete DGG set