You can get scraper blades, both stiff and flexible, for most multitools. Old, blunted multitool saw blades can also have their teeth ground off and the edges sharpened to make low cost stiff scraper blades, too. Multitools are slow and noisy, though, but still quicker and easier than doing it by hand.
. Been reading about these old type of tiles and they could contain asbestos. Heating seems like a good option as less chance of the breaking into multiple pieces.
I'll get them tested just to be sure.
I think they are crafton tiles. Or something like that. They could even be early Amtico. Think either don’t contain asbestos though. But worth checking. The old brown/ Black 9”x9” tiles mainly do.