And had a pretty good time! Definitely seemed shorter than our games of 40k at around 2.5 hours, even though it was our first game. Tried using 9e Tempest of War missions which was probably a mistake as most of them don't make sense with alternating activations lol (and my opponent was guaranteed victory when he drew Raise Banner, Secure No Man's Land, and Tempting Target all on the same turn). Most of the proxies made sense, though there's the odd weirdness like primaris units having 2+ saves but still only one wound.
Other thoughts: Tanks felt super tough but otherwise weak unless you spend tons of points on upgrading the main guns, which was disappointing. 2k points definitely felt low. Psykers were more complex but pretty fun. The decision of whether to activate what you wanted or something that would probably die if you didn't activate it right now really added some extra pressure that I enjoyed.
RIP my Manticore that died first activation to a Scouted ATV with a Deadly (6) multimelta.
Final Score: Imperial Guard 65 - Space Marines 78
I get the point about factions. For me it was mostly a lore problem since I dig the visuals of most factions (except Ariadna) I wanted to go for Yu Jing first but I really don't vibe with the lore. It reads like someone took the China that exists in the head of liberals, reintroduced an Emperor and send them 180 years in the future. Noooo thanks.
In the end I decided to go for Haqqislam instead, they aren't without problems either but they don't make my skin crawl.
I also agree on the Kitbashing aspect.