Yes it's normal upto certain temperature... but if it exceeds 40°C don't use it, buy a genuine one. Though I personally recommend you to buy a Samsung Og charger because only a samsung's charger can maintain the battery life of Samsung phone.
If you are using samsung flagship then you have to buy an adapter. Only one other option i can recommend is apple adapter.
Realme/oppo/oneplus/vivo/iqoo these brands have diff. Fast charging technology. Samsung supports pps charging technology. If you want to keep your battery healthy for long term then stop using realme charger from now.
Kindly use original Samsung adapter of 45 w. 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.
As per your concern, we want to inform you that we do not recommend using any hird party charger for charging Samsung devices. So, Kindly use a genuine Samsung charger for charging your device. However, kindly perform the following steps by the given links to resolve your issue: https://www.samsung.com/in/support/mobile-devices/how-to-prevent-the-overheating-of-your-galaxy device/#:~:text=Please%20be%20aware%20that%20the,damaged%20or%20incompatible%20charging%20cable.&text=Next-,Disconnect%20the%20charger%2C%20and%20close%20all%20running%20apps.,authorized%20charger%20and%20USB%20cable.
If the issue still occurs, please visit the service center for a physical device inspection. You can locate your nearest service center with this given link: https://www.samsung.com/in/support/service-center/
