Lüneburg is nice not big very. Football scene? Not particularly only small league team there think its in 5th or 6th level of german football. think level is right word for english? please correct me.
But you are only located like 30 maybe 40 minute drive from st pauli. so go there! dont go to hsv or ill have to "slap you"

closer i think to 40 minutes university on south western side of town
Nothing great besides university there only real famous thing is Himmler killed himself in Lüneburg. He buried anonymously somewhere in area around it just spit on random ground and maybe with irish luck it will be his grave
Scenic? Perhaps for you there are some good locations in Lüneburg to look at. Especially water tributary in Lüneburg and houses by them up to water. Also outside it is beautiful as area around town cleared of trees and is just plain land. To me looks plain but others like the look.