I have never played a Beethoven Symphony, nor a Brahms Symphony nor a Shostakovich Symphony nor a Bruckner nor a Mahler symphony (apart fromt the Adagietto of the fifth). This is most purturbing! I suppose they are generally avoided by Youth orchestras... (although I have seen YOs play Shostakovich 5 and 10...) I've played 4 Tchaik symphonies though! (2,4,5,6)
Aren't you in CUMS? I never was myself, but you ought to be. Audition next year! My wife was (another cellist) and amongst lots of other big Romantic repertoire she played Mahlers 1 and 5 in her time there, as well as lots of modern stuff. Another highlight of CUMS during my time there - and there were quite a few - was Dan Harding's 'heroic return'; he put on a very intense
Rite of Spring. They are - or were - a really fantastic band, as you'd expect, with fine established conductors or conductors-to-be, very committed, talented players and often working direct with the composer.
In my YO days I never played a Mahler symph either, though I did do Shostakovich 5 in Les Invalides (a phenomenal performance, believe it or not), which was one of life's great experiences. And amongst other things we did a few British premieres (Kancheli, Woolrich) under Martyn Brabbins. That was the LSSO (Leicestershire) of Tippett/Pinkett/Brian symphonies fame, though I was in it a couple of decades after those glory days, in which it was once voted best youth orchestra
and best amateur orchestra in Europe IIRC