hi, have you tried to search the forum?, there are a number of posts about running rclone on routers, including openwrt.
for example,
https://forum.rclone.org/t/rclone-serve-dlna-performance-issues/26808/9
and it is important to understand, that there are two vfs caches.
vfs dir cache use memory
vfs file cache does NOT use memory, does use local storagehttps://forum.rclone.org/t/status-about-using-rclone-for-music-storage-playback-in-2021-access-times-improved/27648/34