Is it just me or is invasion bugged?

This is my attempt to invade the Drengin homeworld at the end of the tutorial. As you can see I have a 10:1 battle advantage, a +40% soldering bonus and a strong  tech advantage, and I've also nullified resistance with biological warfare.

Not only do I lose, but my invasion force is slaughtered to a man, while 50% of the defenders survive. I even lose all my transports. The numbers don't even add up. Apparently I lost 3 times as many soldiers as they did (1,501,061 to 540,611), but I started with 3 times as many legions as they did, and while I was left with none they were left with 5 legions. So actually I lost 6 times as many legions as the defenders!

So if that force only managed to kill 50% of the defenders that suggests that a force of twice the size would kill _all_ the defenders. But if I wanted to win comfortably without losing most of my invasion force I might need what, 3 or 4 times as large a force as I already have, so 9 or 10 to 1 numerical advantage? So what sort of battle advantage should I be looking for, 40:1 or something?

Prior to invading I already found it irksome that I couldn't even determine what ships are defending a planet before attacking. If I encounter a fleet in space I can see what ships are in it, but if they are defending a planet they are invisible? I do get an indication of my chances of success before attacking the defending fleet, but without any indication of what type of ships are defending the planet I have no information with which to adjust my attacking fleet.

Before invading the planet I can see I have 3 times as many legions as those defending the planet, but no indication of the chance of success and no option to back out before committing to a doomed invasion.

There is an annoying pattern emerging of not having the necessary information upon which to make an informed decision. Possibly I could build an advanced spy network to acquire this information, but if that's the only way to get this information then that's seems like a shame as it's no longer an option but an additional required step. Options are good, they give the player agency. Additional required steps are bad, they just create more work without adding interesting mechanics.

Incidentally, how do I study the design of an enemy ship I encounter in space, see what modules it has fitted and so on? I've ready the manual and I don't see anything about combat at all. There is a decent amount about how to design your own ships, but really what's the point if you don't know what kind of designs the enemy is fielding?

Are addional mechanics in these areas present in the main game waiting to be discovered?