Is it the same continuity? It can be!

Potential spoilers below for the various Hammer Frankenstein films.

Everybody assumes that Evil can't be reconciled to Curse/Revenge but I think it can. The only real leap of imagination required is the idea that Victor owns a second property and has set up a second laboratory there (something which he would really need to do during the events of Curse). Since we see those events filtered through Frankenstein's story to the priest, I can't see any problem with that. He simply excludes those secretive activities from his account.

The sequence of events then goes as follows:

The main body of Curse, but with Frankenstein as an unreliable narrator. His growing rift with Paul and the presence of Elizabeth in the house leads him secretly to construct an alternative laboratory at his chateau near Karlstaad (across the border in Austria or Germany).

After the disaster at his original house, Victor escapes (note that there is no arrest scene in Curse) and, at the chateau, resumes his experiments with a second crude monster, an exploit that leads to his arrest (as we see) and his return to the Swiss authorities.

His trial takes place but without any input from the Karlstaad witnesses.
He is convicted as an ordinary murderer.

The framing sequence in Curse takes place and he is led out to the guillotine. However the execution is halted possibly so the growing stories about his monster-making activities can be investigated.

A brief second trial takes place and he is scheduled for execution again, this time as the more notorious figure we see in Revenge.

Then the events of Revenge, of course, his career as 'Dr Stein' and his meeting with Hans Kleve.

Revenge leaves us with a dangling plotline in London which has to be resolved in our imaginations anyway as no subsequent films address it.

Following whatever your preferred resolution to 'Dr Franck' is, we eventually arrive back in mainland Europe and the story of Evil. The flashback, told by Frankenstein to new assistant Hans, is Victor's sanitized version of the events in Karlstaad, leaving out the bulk of the story and with an outright lie about being exiled rather than sentenced to death. (Hans isn't Hans Kleve so he knows little about what really happened).

To me, that all fits together okay although I'm not suggesting that any of it was the intention of the various film-makers.