Solid Explorer
There are literally dozens you can side load I use fx which does the job.
I also recommend FX File Explorer . It has a good UI and does the job.
X-Plore is very popular and also good to use with a remote.
The free version has probably enough features but they recently added some ads to it. If that bothers you, you can simply download a slightly older version from apkmirror.com and sideload that instead. But longterm imo X-Plore is very worth buying.
Fx and xplore
Fk file commander
You don't really need it , I use Fire Tools it will connect to your Android TV remotely and you can move around what you need.
CX File Explorer is a good one with local network support. One has to sideload the app as it is not available on play store for Android TV.
You can use this file manager on your tv https://play.google.com/store/apps/details?id=dev.dworks.apps.anexplorer
x-plore file manager or try another one