Isolated board design suggestions
Circuit seems ok regarding isolation. you should also take care when designing the PCB and keep enough distance between the isolated side and the uC side. Also do not mix traces from the isolated side with traces from the uC side. Doing board cut outs under the isolation ICs and the isolated supply is also recommended.
Also consider the rating of Isolation of your converter and isolation ICs. Normally they are rated for 1 second and your should convert to continuos operation. See the following calculator.
https://recom-power.com/en/support/tools/isolation-calculator/isolation-calculator.html?0
Regarding isolated DC DC converters you have many options with more than 1W power. See following link
https://www.digikey.com/en/products/filter/dc-dc-converters/922?s=N4IgjCBcoKwOwGYqgMZQGYEMA2BnApgDQgD2UA2iAEwAsAnGHBMVQmFTDCCwggAwAOAGzdqvAXT6iqQuDRhUQAXWIAHAC5QQAZXUAnAJYA7AOYgAvsTA0myEGkhY8RUhWqCFNaYLhCpLPjoEAThvBkFpMD4qKjowgQlIwTABSOshJBZ6RggVEA0tXUNTCysFLmh7DBwCYjJISloghmls2yy6BVCOmhpUjph6aSEYfzE%2BPhTpfjAYETyCyB19YzNLahTQyocnWtcG8AACAHVRMAA6DhOz85hrq3OBe%2BpnhGeaZ7vT4iFrhc0lgBVIwGdQAeXQAFl8JhcABXPT4UrUKhgCDbarOOpuXJqAEgACSRnU%2BBM%2BD0FnWigOABMUIc6YcUCQjAA3ckkilKcxAA
You also need to isolate your CAN and RS485 signals. I'm used to working with SPI and I2C signal isolators but just google RS485 isolator or CAN isolator and you will find many options.
For I2C isolator I have used Si8602AC
For the CAN isolation you have for example ADM3053