The first thing that comes to mind is Commander One, which in my opinion is the most similar to Total Commander, both visually and in terms of functionality. It has the classic dual-pane layout with a built-in FTP client. It gets good reviews. Another good one is ForkLift. It doesn’t get as much attention, but it’s got that dual-pane setup and works great for FTP/SFTP transfers. It’s paid, but if you’re after something simple and no-frills, it’s definitely worth checking out.
FileZilla is also an option, although it doesn't have a true two-panel layout like the options mentioned above. It’s still a solid FTP/SFTP client, especially for basic file transfers—but if you need that dual-pane experience, it’s not the best choice. All three offer quite similar functionality, so it really comes down to whether you need anything extra from your FTP client. Try a few and see which one clicks with your workflow. Each of these is supported and will run natively on Sonoma.