I’ve been looking for a way to track the performance of my portfolio across different brokerage accounts, currencies, stocks not quoted on Yahoo Finance e.g. for a while, and the other day I found this - https://www.portfolio-performance.info/en/
It appears to be developed by a German open-source community but they have an English version available and it’s fairly comprehensive. You can manually add stock/quotes, adjust for dividends, draw data from Yahoo Finance (and others), make charts etc. and it automatically converts foreign currency to the currency of your choice.
Here’s my portfolio over the last year compared to a Vanguard Global Index fund, I’m very comfortable with my positions but good thing I don’t have investors.