Try Material Files file manager. It’s the best file manager I’ve used, connects to remote servers, and is open source

https://github.com/zhanghai/MaterialFiles

The best part is it works with Android as well. Whenever I turn my computer on, all my photos on my phone sync to my computer to a folder that gets regularly backed up (using Vorta which is an excellent and easy to use open source backup program for Windows, Linux, and Mac)