Thanks Alan, need to try again and will take your offer from the support, if and when needing it.
What I understood I was required to do was that I needed to add DENO INSTALL as a key with /opt/render/project/.deno value to the envirionment variables section. Then I set curl -fsSL https://deno.land/x/install/install.sh to be a build command and
finally I added export PATH=“$DENO_INSTALL/bin:$PATH” && deno run --allow-all app.js in the start command.
You likely already see what I’m doing wrong so pls 
-Jouni