I wouldn’t worry about it being dated - names come round again. In 30 years time Ada, Ava, Archie, Elsie, Isla, Olivia, Tilly, Freya etc will seem dated as a lot of the people with those names will be approaching 40 (same as every other girl I went to school with in the 90s/00s was a Sarah, Chloe, Hannah, Becky/Rebecca, Abigail, Grace, Katie, Lauren). Obviously a lot of these names have been widely used for centuries but there will always be a cluster due to trends in popularity. Look at how the ‘old people’ names have come back - Margot, Elsie, Stanley, Edith, variants on Reggie etc. Elsie could be 5 or 85. There’s a very real chance that the next trend will be the more 70s inspired names as babies are named after their grandparents, the 40s-50s names become a bit too overdone etc - a baby Joanne/Joanna could be ahead of the curve!
Like most people on here I prefer Joanna, also like Josephine, Joan(/Joanie), Josie etc. If you like the name I wouldn’t write it off based on concerns about dating as it’s something we have no control over as individuals!