Great suggestion and urgently needed. I wonder how people solved this problem until now?
If there is a custom token functionality we could use the token address from etherscan/bscscan/… and save it with the custom token. Whenever this token gets officially listed, Accointing could remind us that this token is now ready to switch over to the automatic tracking.
As long as the token is “custom” we are self responsible for the price data at the time of trades. This seems quite manageable for me.