Any other way to turn into a vampire?

There should be several random game-generated townies who should be able to turn your sim. Check in the unplayed households. Be advised that it may take some time to track them down.

If you don't feel like going through the population with a fine-toothed comb, you have three options.

1. Use the Vampire Nexus lot trait on one of your public lots and visit it late at night. Nightclubs and bars are particularly effective at drawing vampires.
2. Take a lap around a neighborhood late at night. Typically you can find one of two types of sims -- actual vampires or vampire poseurs. While Forgotten Hollow is the obvious choice, I have found that Bedrock Strait in Oasis Springs also spawns a high vampire percentage in the wee hours.
3. Start a new game with a vampire you made yourself. Either play with them long enough to gain enough skill points to purchase the ability to sire or use cheats to get the points fast. Save the sim in your gallery and then put them in your main game where you want them.

EDIT: I suppose the fourth option would be to use cheats to give yourself the vampire trait, but I'd advise against that. It can result in a bugged sim who won't gain power and penalty points correctly. Best to do it via one of the in-game methods.

If the vamps you create don't have the power to turn it is likely you will have to level them up a bit (bit, get it? Sorry) to get that particular perk.

There are several Maxis-made vampire households on the gallery; you could add one of them into the game and ensure at least one has the vampire creation power. (And many player made vampire households as well.)

Vatore's not around anymore?

You can either use the Vampire Traits or go into CAS & select a Vampire Occult.

There are cheats to make your Sim start the turning process or become a vampire immediately. I think there's a good explanation of the cheats at Carl's Sims 4 Guide. https://www.carls-sims-4-guide.com/cheats.php

Caleb and Lilith Vatore both have the Vampire Creation power.

MCCC has an option to make someone a vampire I think.