What do you suggest as best portfolio tracker that's not connected to any wallet?
One fo the best way option is to register and create your portfolio on Coingecko website, but remember to use some temp email you are using only for that purpose.
Coingecko also have apps for Android and iPhones, so you can install and use that on your phones as well (you don't need to add any wallet address information).
Alternatives for Coingecko are Delta, FTX (ex Blockfolio), CoinStats and people release new stuff all the time, I even saw one posted in bitcointalk forum few days ago.