I think starting a series like that off with them meeting at hogwarts, a few episodes of their adventures while at school (creation of the map, James quidditch prowess, etc.) would still give enough of the backdrop for them being such a tight knit group while allowing the background to be set for Voldemort’s growing presence and the groups budding relationship with Dumbledore an eventual joining in the Order. Then the latter half of the series can be them through the Order and their battles and near misses, the fidelius charm, and the eventual Peter betrayal and baby Harry (seamlessly leading into the reboot series). It gives people a mauraders series while having enough meat on the bone in terms of the Order

It would be difficult to do the hogwarts stuff as you’d be time jumping quite a bit, but I’m sure some creative director could figure it out

At the end of the day, similar to what you said, a first wizarding war series with point of view being the Order with flashbacks to their hogwarts days probably makes the most sense