There's no option in hPanel to switch the File Manager back to the old layout, at least none I can point you to. The new one is what everyone gets now, sorry it's slowing you down.
A couple of things that might make it less of a hassle:
- Browser view is the closest to the old file-explorer feel. Use the Browser / Editor buttons in the top-right corner, and File Manager remembers whichever you used last.
- If you'd rather skip the web File Manager altogether, connect with FileZilla over FTP. In hPanel go to Websites → Manage → Files → FTP Accounts for the host, username and port
21, and upload into public_html. On Premium and higher plans you can use SFTP on port 65002 instead (enable SSH access first).
What part of the new layout gets in your way most? Uploading, editing, finding files? If you tell me, I can point you to the quickest way to do that in the new version, and I'll pass the feedback on.
Full guide: How to use the Hostinger File Manager