I confess to being underwhelmed by this latest update as well. I was really hoping to be engaged with Thargoid foot soldiers by now - something that would give the foot combat-focused mechanics of Odyssey greater purpose at long last. Sadly, nope. Not yet, anyway. But even beyond that, I have never found the Thargoids to be a compelling enemy. For space bugs, they pale in comparison to, say, Tyranids or the Zerg. I just don't fear them (perhaps it is the odd name that sounds like a disease - "Sorry, I can't come into work today. I have a bad case of thargoids on my feet.") Whatismore, I find this dust-up between mankind and the Thargoids to be morally nebulous at best. Like others in this thread, I am content to sit it out for the most part, with only the occasional dabble.
Having said that, I do understand why FDev went in this direction. Odyssey needed a big kick in the pants to revive the flagging community, and nothing gets people excited like a binary-choice war, particularly in a space game. Looking at the numbers on Steam, this strategy has paid dividends as peak player numbers have received a bump not seen since ~early 2020. The strategy worked! (Coincidentally, it is also the same decision CCP made to bump Eve's flagging numbers - in their case, their comprehensive overhaul of faction warfare that also allows players to engage in combat, as well as support functions for the more peaceful players. And the entire thing is opt-in as well!).
I also have to tip my hat to FDev. Developing an AI opponent on this scale is no small undertaking. As someone who enjoys sparring against chess bots, I am getting a kick watching FDev's bot take on human players. Honestly, I would have preferred the enemy to be an actual bot instead of space bugs - a return of the Guardian AI "constructs" would have been much more attractive to me. Heck, FDev might still have this in mind as a future chapter. As a fan of Fred Saberhagen's Berserkers, I can only hope!
[As an aside, I find this AI-driven war to offer tantalizing opportunities. Next year we are expecting an overhaul of a major game feature. Imagine if it is going to be a revamp of PowerPlay that takes advantage of the work done on this Thargoid war system? That could be a lot of fun! Something much closer to what I think most players had in mind when PP was announced.]
Back on point: I do wish there were options to aid the Thargoids. It would have been fun, and really, really interesting, if there was a Thargoid contact players could seek out and get missions from for special thargoid rewards, etc. Or maybe even a third party fighting against both or seeking a separate peace (this would be closer to what the OP wants if I read it correctly) . To be fair to FDev, each party they add to the war scenario takes an already complex system and adds another layer of complexity. I suspect FDev have their hands full just managing this simple 1v1 setup! Even allowing players to help the Thargoids probably would add so many variables to the war that FDev would find itself managing a nightmare of complexity. I agree with the OP but I also see why FDev is keeping it simple, at least at the moment.