First of all thanks for your great work mahajant99.
Installed this 20210310 release few days ago on my X3 NFC, coming from the EU stock ROM 12.07. It's all good and the battery only loses few % each day, which is truly amazing! I have WIFI and mobile data working right from the start and so far it's a great experience.
However there are some things that do not work yet:
1. Recording and sending Video via Signal or Telegram works, but i can not play them back in the app or gallery. They play fine on another phone, a PC or VLC app. I guess this is what was pointed out in comment #166 already. Works flawless on the stock MIUI EU ROM
2. Probably related to #1: Tidal HiFi app does not play anything. It remains stuck at 0:00 and you can not scroll through a song either. You can try without an account, but only(theoretically in this case) listen to 30s of each song. Spotify was also tested and works. Seems to me like a codec's missing or something, idk? It works on the stock MIUI EU ROM.
3. ext4 support for external storage and TF card. TWRP supports it and i checked with a Samsung Galaxy S4 running LOS 18 too. It works there. Since i'm coming from a Sailfish X phone, this is mildly annoying. There, ext4 is the default fs for TF card and external storage and it makes way more sense than FAT32. Also, most LOS ROMS support it, so i guess it's easy to do. I could be wrong however.
4. WiFi HAL crashes and disconnects when it tries to connect to my home wifi router using another captive portal check provider. It throws some SSL exceptions which i can see in logcat. I fixed this by disabling local DHCPv6 which is not needed anyway. I crosschecked this with Galaxy S4 and S5 both also running LOS and it works there. I wouldn't prioritize on this too much since i found a fix that works and is most likely not your ROM at fault.