Yahoo uses the CRSP method (see: factor to adjust price) to back-adjust old prices when dividends and splits occur, so it's not as misleading as you're probably thinking. I'd be surprised if the others didn't do something like this too.
Their charts are price-only. Same with Google Finance and Apple Stocks.
EDIT: OK, I see there's a note that close is split-adjusted but not dividend-adjusted.
The price increase at earnings announcements is (to a first order approximation) indicative of the extent to which the company's earnings exceeded the market's expectations. It's as likely to be positive as negative. Otherwise you could buy the company's stock the day before the earnings announcement and get yourself some free money.
Using SPY I can easily see the non adjusted returns from the bottom of the GFC to the top in 2021/2022 were a little over 600% but then accounting for dividends see it's actually a bit over 800%.
https://totalrealreturns.com/s/SPY?start=2009-03-09&end=2022...