@Flood and Flood's wife
You're right, Google's Find My Device has no such function to unlock your phone, that was my error.
But the way that my phone's reset happened was quite an oddly hilarious thing:
I did requested a data wipe on the Kaspersky site, but the command isn't going through because, apparently, the site thinks that my phone isn't connected to the internet (I assume in part because I had drained the battery on purpose and turned it back on again to see if that would do anything, it didn't).
So I went and looked around some more to somewhat try unlocking my phone, preferably without going to a specialist.
And I had chanced to somehow remember that Samsung SmartThings Find does, in fact, have that kind of function. I went to the site and clicked the remote unlock button, it worked flawlessly.
But as soon as it worked, of course, Kaspersky's data wipe command also came in, that means all my data gets wiped right then and there. As I watched a metaphorical milk spill out from a bottle I had just opened.
I won't recommend you try to data wipe to see if it works, but the remote unlock did in fact worked.