Working backwards ...
I usually scout very thouroughly, kinda failed to do so this time as things where a bit harder to get going .. ahem
Still need to unlock mk3 scouts or finish setting up my initial terf, I was aiming at the last but seem to need to do some scouting first.
Iirc 7.3, could be 7.6. A Bully and an Assassin. I just get punished too hard in this game to "try" any harder without things at times becoming somewhat frustrating, which I like but does require some care to not overestimate ones self
I do not lose planets
(Havent yet in this game.)
Just to have it said explicitly, I hope this is a feature, even if it isnt intended I do like it. When you think you finally have the power to clear a planet you get a pop-up telling you about "[~size of own fleet] number of enemies incoming" and 20s later they are there forcing you to make some hard calls.