I've been tinkering around with my 11 speed mechanical gravel bike and picked up an LTwoo GR9 (with stabilizer) rear derailleur. Make note there are 2 versions of LTwoo's GR9/GRT rear derailleurs. One with stabilizer and one without. Anyways, I paired it up with Shimano 11 speed Ultegra shifters, Pass Quest 34t chainring, SRAM 12 speed GX chain and ZTTO 9-46t 11 speed XD cassette.
This setup was tailored to tackle the steep mountain trails in my area. Surprisingly it shifts great! LTwoo uses the Shimano 10/11/12 speed road/gravel pull ratio, so everything works perfectly. In fact I would probably opt for this rear derailleur over the 1x GRX 812/822 RD (even if running 12 speed). I prefer Shimano shifters over LTwoo shifters and this Shimano shifter/LTwoo RD combination works much better together in my opinion.
