I agree LK 6x6 was way harder than 9x9 (though having just watched Kishore solve a LK by RSP on their YouTube channel primed me for some of the intended sum logic for the 9x9.
I also just solved 9x9 skyscrapers after about 2 hours with the help of the f-puzzles solver to help me get the break-in.
The submission of results are taking a little longer time, in comparison to the previous contests. For analysis purposes, the speed of my broadband network was 100Mbps.