um, hi! we don’t know each other, I found you through pixel-art tag on itch-io. I read the comments here and I had the same issue with one of my friends – they weren’t able to use any messenger. we ended up using yourworldoftext(dot)com, you can create a new page there, like yourworldoftext(dot)com(slash)wordhere and you can type there, it’s basically an endless sheet of paper. it’s online and it’s visible for anyone who will type the same word! so you can use something hardly-guessable and talk there. be careful tho, like don’t share any sensitive details and so on. also some people just delete everything from every page they open, so like it’s possible. but still, if you literally have no other place than… also you don’t need and account, it’s just a webpage. take care!
ps: I made a (slash)circaetuscinereus page there, you can see how it looks