If you are using a rooted phone, most likely you'll have Magisk root manager might also have been installed. If you are using any other proprietary root manager, I highly recommend you to move to magisk as it is Free and Open Source and some of the features it provides like hiding root and support for modules.
Manjari is my favorite Malayalam font and it is such a pleasure reading text formatted in it. The default Malayalam font in Android - Noto Malayalam on the other side, even though it looks good for user interfaces, is not good for reading long forms of text.
I created a couple a magisk module for Manjari and later ended up packaging all SMC fonts in a single module. Joice from SMC team wrote an easy, how-to-use guide for it. You can read it in SMC blog.
https://blog.smc.org.in/installing-smc-fonts-on-android-devices/