yes you can increase the RAM i also increase the RAM of my laptop rental and its working fine. there is only one thing you need to take care off if you are using a DDR3 ram the 8GB ram should be DDR3 if you use DDR3 ram with DDR3 ram it will not work and also damage your motherboard

i never face an issue like this on my hire laptop in melbourne. might be possible there is a problem with you AMD ryzen 5 3600. check it on another motherboard