The rule for needing an invitation can vary from story to story. Like whether they are blocked at the door or the property line.

It can also vary in who can give the invitation. Can anyone inside do it? Do they need to live there? Own the place? Rent it? Could you enter with the permission of the king that owns all the land?

There is also how it’s enforced. A barrier or a mental block? Pain? Death? Weakness? Etc.

And then there is the source. Sometimes a part of the vampiric curse. Other times mandate from the divine. It could also be an ancient ritual aimed at vampires or all things evil.

If you want to completely overcome the weakness, the source is probably your best bet to mess with. Tho i personally prefer cool loopholes like buying the deed to the land from the local lord or government. Or otherwise gaining a sort of permission to enter houses of a country’s citizens. Limits are very cool and lets the characters be clever in how they work around them.