First you need to get a good oven thermometer and measure the temp in your oven. Run the oven for about an 1/2 hour and look at the thermometer. If you set it for 350° does the thermometer show 350 or higher temperature.
Our oven is 25° hotter than the setting so we have learned to live with it. Instead of 350 we set it at 325 when we use the oven. Most of the time we use a countertop convection oven for convenience.
An adjustment can be made to reset the oven so that it maintains a near correct temperature. You'll need to look at the owners manual to find the adjustment.