Modern "landlines" when used with DSL or fibre are also no longer "true" landlines, instead the modem/router acts as a SIP client and gives you an FXS port to plug an analog phone into. While it could theoretically emulate this behavior (by keeping the SIP session open for a few more seconds), I don't believe any of them do - in any case it's trivial to test by calling a different phone that you control, hanging up on your "landline" and seeing whether the other phone hangs up immediately (it should) or if the line is held open for some more time.

If this is still a thing (I frankly don't see the purpose of it), it would only apply to real landlines where your phone is directly connected to your phone socket without a modem/router in between.