Steam Deck had a few struggles back and forth during launch, but the improvements are already stable and coming one after another. Especially the stock issues were pretty tough though.
Examples of the resolved issues are fan noises and amount of games that are working at an optimal level. Fans took an update to stay quiet and initially low number of games that are working on the platform quickly increased both via verification procedures and some tweaks around the settings. Now we have another update coming from Valve, which will make players quite happy.
Valve is adding performance settings which are available to adjust separately for each game with the next update for Steam Deck. Each game will have its own performance profile with this change. This new feature can be found in the Quick Access menu, and then navigating to Performance, and Advanced View.