(Someone seems to have asked something, but then got banned and all posts were removed, so my answer below hangs in the air.)
In the elder speech in some regions, it really was like french ou, IPA [u], but this pronunciation is not part of the standard Swedish pronunciation.
The short Swedish u is a rounded mid-central vowel, and the IPA [ɵ] seems to be an accurate categorisation, unlike the treatment of some other Swedish sounds.
The short u is only rounded, while the long u is over-rounded, and these two sounds are very different.
The over-rounding occurs with o [u] and å [o] as well, but in these cases there is no major difference in quality between the long and short quantities.