Just want to chime in to add another vote for hnyman's build here. I flashed my Netgear R7800 with hnyman's stable build of OpenWrt a couple weeks ago. Flawless experience, and it's my first time with OpenWrt.
I had some issues related to PPPoE (I am on DSL) that turned out to be a line problem that my ISP corrected on Monday, and since then I've had flawless uptime. I use cake > piece_of_cake SQM and get A and A+ on dslreports bufferbloat scores, whereas with stock Netgear firmware (even with QoS on) I saw consistent Fs.
Here is the thread for hnyman's R7800 build with links. He's been maintaining this for years:
https://forum.openwrt.org/t/build-for-netgear-r7800
I've flashed the upgrade packages twice since installing OpenWrt and they installed flawlessly both times.