You can use a tool like Warudo to export into a VRM format, without having the Warudo program:
https://www.youtube.com/watch?v=IvYUOKglJVc
Theres also this method, but i've had less success since it does deal with older Unity versions.
https://www.youtube.com/watch?v=0hF5_A3_nL4
Feel free to let me know if you have any questions! (˵ •̀ ᴗ •́ ˵ ) ✧
