I have not routed a minimum kills run, but I have routed a "minimum use inputs" run, which is also a minimum kills run by default.

("Minimum use inputs" meaning least sword, watering can and potted petalportal uses.)

The minimum use inputs to beat the game is 128.

Yes, quitting to the menu and reloading is faster. But sadly it is not allowed under the any% igt rules, as the act of quitting out of the game breaks the in-game timer.

No speedrunning discord server specifically

controller allows you to move in all directions, as opposed to just 8 on keyboard. i also find most frame perfect tricks to be harder on keyboard but that might just be me skill issueing

i forgot to mention that in the drawing, the controller is resting on my right lap, which in turn rests on my left lap

both the animation skip when taking items and small mayor onion are done with a frame perfect pause, you can look at the input display on the wr and replicate the timing. as for the controller grip, i have beautifully constructed an artists rendition: https://cdn.discordapp.com/attachments/821411567089614928/1174949668724158484/Untitled28.png?ex=65697426&is=6556ff26&hm=d5add499136022a3a51ad6faed6557a3cb09274223580e834f642cf431d0e84b&

what kind of guide are you looking for?

If you have to pick one or the other, controller is faster. However, most runners including myself play on both keyboard and controller because text mashing is generally faster on keyboard.