About the odds you will face, nothing. About the operator, a little, if you watch for the right things.
The odds part is straightforward. A game's return to player is set in its configuration, not in the sequence of results on screen. Rounds do not carry memory, so a win does not make the next round less likely to win, and a losing run does not build anything up. This holds however large the sample on screen, and it holds whether the account is funded by the streamer or by the operator.
The complication is that the same game title can be configured differently at different operators. Stake Originals run at 99% RTP, a house edge of 1%. Spribe's Aviator has a 97% version, and operators may configure it at 96% or 94% instead. Spribe's Plinko is 97%. JetX ranges from 96.2% to 98.9% depending on configuration. So the version a streamer is playing may not be the version you are offered, and the difference between 97% and 94% is a doubling of the price you pay per unit staked, from a 3% edge to a 6% edge. Whether an operator discloses its configured RTP per title is one of the things our score measures, and our RTP simulator shows what those differences do over a session.
What a stream can show you honestly is the interface, the deposit flow, the game catalogue, and sometimes a withdrawal being requested on camera. That last one is worth watching, though a withdrawal by a sponsored account is not the same process a new account goes through. Verification requests tend to arrive on the first withdrawal, not on deposit, and a streamer's account was verified long ago.
If watching has started to feel like research rather than entertainment, our responsible gambling page lists limits, self exclusion and support services.