I own an Xiaomi Mi A1 with LineageOS 15.1 (unofficial) and microG installed. There are three problems:
OTA wasn’t working when I installed the ROM, so no easy updates. Encryption had issues when I installed the ROM and there still seem to be some now. Encrypting on stock ROM is recommended. There’s a problem with Whatsapp and microG, when first running it. My aim is to install the official LineageOS 15.