I already saw that there is a kotlin folder in the SDK under tools\lib\external\org\jetbrains\kotlin with the 1.3.72 version of those two files file so, per your suggestion, I copied them to my additional libraries folder, referenced them with #AdditionalJar and that seems to work so far
I wonder if there is a way to get the B4A IDE to use them without copying.
No. I meant for the IDE to include them from the SDK without hacking around. The copying is a once only task anyway so there is no point in scripting it.