In wargaming this is called a campaign.
A campaign can vary in scale from following a squad through a linked set of skirmishes to the scale you are suggesting of armies fighting.
A campaign can vary in complexity, and size, and is very much down to the number of players involved and the willingness of the umpire running it, and most are the efforts of an individual (or group) rather than something commercial . I can’t say I’ve seen a WWI campaign on the scale you are thinking, but that isn’t to say there is something out there.