Please reset network setting of both Sim one by one and than reset all settings of your's device in general management settings also Flight ✈️ mode on n off one time, restart your's device without any Sim in slots also interchange Sim in slots also turn off power saving mode then go to wifi settings and click on intelligent wifi then try to it's again. If you like please accept as a solution it's help to others users also, click on 3dots in my reply section and click on accept solution. Thanks.
In case the issue still occurs, please visit the service centre for a physical inspection of your device. You can locate your nearest service centre with this given link:https://www.samsung.com/in/support/service-center/
