Finally vanilla PuTTY now can support keyboard mode used by far2l in tty mode, so most of keys should work even in unpatched version. The right settings are Xterm 216+ and xterm-style bitmap:

But Shift+Control+Arrows are still not working. I investigated escape codes that PuTTY sends in this mode. For Control+Shift+Right it sends ESC[1;6C — just the same that GNOME Terminal sends. But in far2l Shift press is still not seen.