When Van Helsing explains what truly scares Count Dracula in the 2020 TV-series, she says it's something that explains all his "smaller" fears or restrictions:
- fear of the cross
- fear of the Sun
- sleeping on his origin land soil
- entering private property without an invitation
His biggest fear seems to be fear of death and that's why he keeps on sucking that girl's blood, because "she seems to be not afraid of death"
The thing is, I can accept that the cross represents the commitment of Jesus to die, the soil representing his eternal rest underground and the Sun that we believe it will kill him scares him...
But how does this bigger fear explain why he can't enter without an invitation?
Note: as seen the Sun is not really harmful for him. It's part of the folklore that even he believed to the point of immense fear.
Could be similar with the invitation. Either way, that he absorbs the myths is not just the one explanation that Van Helsing wanted to find as one unique truth.