There's no WinSCP 5.4.3. Did you mean WinSCP 6.4.3?
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.
Windows 11 24H2
WinSCP 5.4.3
When it freeze, it could take from few seconds to few minutes to unfreeze. It happend by browsing, in the preferences, when navigate in other programs and comming back in WinSCP. I could be during transfert or not.
The transfert continue in background.
It now seem related to the session.