When I got Waswas I started to check myself every morning for mani, and used to take Ghusl all the time but came to understand it was mathi. So now I just use the bathroom and change clothes everytime I wake up. Is it a must to do this as I’m not 100% sure but there is a chance there could be mathi

When you wake, get dressed and pray and do not investigate, because the more you chase this the more it grows. If these thoughts keep returning, know that this is waswas that you must counter now by refusing to respond to it, and seek the help of a trustworthy doctor, may Allah protect you and cure you.