Trench hammer might be worth a look - its a smaller number of figures, but can’t recall how solo friendly it is.
I play Trench Hammer solo.
It doesn't have any mechanisms for controlling the opposing force's actions (which units activate, what actions they take, etc) - you play both sides. So if you want a more programmed opponent, they aren't a good fit unless you bolt-on a method from somewhere else.
With that in mind, I'd say it's moderately to highly suitable for solitaire use:
It has no hidden elements.
Minimal status tracking - hit points is pretty much it.
Your ability to be "godlike" is limited by the use of an orders roll which limits how many of your units you can activate in a given turn.
It is IGO-UGO, no simultaneous movement.
The inactive side doesn't have any interruptions of the active side's movement - i.e. no overwatch.
Units automatically counter-attack when attacked at "Firefight" range or close combat.
The lack of overwatch might strike some as odd, but it's accounted for (as I see it) by the automatic return fire of that last point. As a solo player, I find that helps me focus on the active side, without having to simultaneously make sure the other side doesn't have an overwatch opportunity.