installing
pkg upgrade
pkg install openssh
To Start SSH Server
sshd
ifconfig
to get IP Address
Default SSH port in Termux is 8022
https://play.google.com/store/apps/details?id=com.termux&hl=en_US&gl=US
TermUX can run Activity Manager) am start commands directly in prompt. Should be good for testing.
Also it can install and run Python 3.