1 volume sonatas beethoven edition?

There isn't a 1 volume edition of all Beethoven sonatas because there are 32 and they're generally published at least 5 per volume to keep their cost affordable. Henle, Wiener Urtext, Bärenreiter are some prominent publications you could consult to buy them in separate volumes instead. Or, look into getting Beethoven: The Complete Piano Sonatas (Alfred Masterwork Edition).