The diagrams are important and show a poor share price...

The diagrams are important and show a poor share price performance over 5 years.
But
Do they account for dividends? As WAM offers a high yield this will make a differece.
Do they account for the rights issues over recent years as they also contribute to returns.

There is no way they are doing a share buyback at the moment.
That would amount to selling shares from their portfolio for $1.86 (NTA) and then using the money to buy your shares back from you for $2.23. As a shareholder I don't think you want them to do that.
Instead they are taking over other companies where NTA is more than the bid price which is paid for with the overvalued WAM shares.
They get the other company's assets cheap and they can add them to their portfolio or sell them and make a profit, this is good for WAM and its shareholders.

All that said, working out WAM's total return is tricky becuase I think they report portfolio performance before fees which are high in WAM's case.
And on top of all that, looking at share price performance, which you are doing, shows that if you bought at the wrong time, returns might not be that great.