You might consider "Bloody Big BATTLES!" (BBB).
BBB was originally created to fight entire FPW battles in an evening. The rulebook includes nine scenarios for all the largest battles of the war. Another seven are freely available in the files of the BBB groups.io group:
groups.io/g/bloodybigbattles
As far as solo play is concerned, BBB was positively reviewed in Lone Warrior, the journal of the Solo Wargamers' Association, as reported here:
link
For collected reviews of BBB, see here:
link
Lots of FPW battle reports on the BBBBlog too.
On the particular question of French passivity: BBB's unit activation mechanism explicitly addresses this in two ways. The first is that the scenarios mostly give the French fewer Generals than the Germans, meaning fewer French units will get the +1 bonus on their movement rolls that a general provides. The second is that French forces in the Imperial phase are generally afflicted with the "Passive" attribute that is a -1 penalty on their movement rolls. These two factors mean the French forces will generally be less agile and responsive and their manoeuvres less well coordinated than the Germans'.
In response Perris's understandable point about players being put off FPW because it seems one-sided: the French army was a defective machine and FPW games should reflect that. That doesn't mean you have to make the player an inept Bazaine or ban him from making different decisions from the historical ones, but you do have to impose some command and control limitations on the French so that the player then has to operate under realistic constraints. Making best use of an imperfect tool is an interesting challenge in its own right.
But that certainly doesn't mean the French can't win on the tabletop. The BBB scenario design approach is basically to take the historical outcome as the "par score". Even if the French can't possibly turn it around entirely and achieve a genuine victory (e.g., Sedan), if they can lose a given battle less badly or less quickly than their historical counterpart, they can win in game terms. BBB games have provided plenty of French victories.
The result of this approach, plus the wonderful asymmetry between the two armies in terms of weapons and doctrine, is to produce really different and interesting tactical challenges and many exciting games that usually go down to the last few dice on the last turn.
Good luck with finding the ruleset that works for you. Plenty of choice out there.