At the very least you need a host with shell access. Ideally on a VPS or Dedicated host so you have all the controls at your fingertips.
Host recommendations for NodeBB?
Find a different host. Any not supporting Nodejs in this day and age are likely lame in many other ways. Save yourself some time and frustration.
I am personally not a fan and no longer use them but Digital Ocean offers low hanging fruit a reasonably modest pricing.