[ZTE Axon 7 ROMs, Kernels, Recoveries, & Other Deve] Infy_AsiX:
Well colour me impressed. Finally decided to embrace AOSP on the Axon7. A few reasons like the recent research findings about security patch omissions on stock and an audio issue on stock pushed me along.

I've only just started testing but here's a few useful points that I think are important to share. I've kept F2FS with Magisk 16 working by using F2FS Loopback Bug Workaround. Searching the Axon7 forum, the F2FS Magisk issue seems to exist but no one had shared this fix. Xposed Systemless 90.1B3 installs fine with it. I'd prefer to use 90.1B2 as some people think it's more stable but I can't find a copy. The big issue I have with this ROM is I can't use my exFAT 128GB sdcard as it shows corrupt yet in recovery it functions normally. Searching the Ax7 forums I've seen mentioned using Magisk 14 instead of 15 allowed working sdcard on Oreo for some people but that didn't work for me. Is this a common issue? Should I try formatting exFAT by some special method for it to work?

Audio

I'm most pleased by how the AK4490 DAC is already always working on headphones. It's actually fixed a couple of issues I had on stock UB32 where using Deep Buffer Remover (now renamed Audio Compatibility Patch) to use the DAC on all headphone audio; plugging into headphones while speaker is playing audio would lock to weaker DAC until audio's paused or also when an app uses the microphone and enables some headset mixer profile (like voice chat).

I've got Viper4Android/Ainur Sauron/Dolby all working together simply and easily by using the Unity versions. There's a few quirks about them worth mentioning. To install the Unity mods you need to reinstall this AML Unity following after for any of them to work. Best to do this in recovery to uninstall and install at the same time, also read the text output to confirm the installed Unity mods are patched. This way includes the V4A driver directly.

Viper4Android

I had a bug when I first tried the new material V4A where unplugging would have the V4A speakers settings not work until toggled off and on again (easy to test this by changing the amp volume in expert settings, when V4A stops working you'll instantly notice a volume difference). Following the instructions I use the old version instead by renaming the zip as I prefer it's driver, UI, graphic EQ and it doesn't have the issue. It's useful that this Unity version has five different variations included for choosing.

Ainur Sauron

I'm unsure on differences with Ainur, but I do notice a little more occassional intermittent static noise with the AK DAC always enabled now so I'll be testing to see if Ainur helps with that.

Dolby Atmos

As for Dolby, I don't like having it. I loved Dolby since getting the Axon7 with stock N on speakers but this install is very different. None of the settings sound anywhere as nice or impressive as they used to, maybe it's a port issue or Dolby has changed, I haven't tried the stock O to know. Also it doesn't automatically switch on and off dependent on the plug state like stock N did, making it a pain to use. I'm just relying on V4A's speaker optimisation alone instead now. Losing quality Dolby speakers on AOSP is a bit of a bummer, but gaining quality DAC while using voice chat apps is a more valuable trade off in my case (note V4A doesn't work with this use case though).