No, you won't be banned . All the people who are banned use the excuse of cheat engine running in the background but Valve can't ban just on assumption.
Having cheat engine open will not cause a vac ban, it may cause a vac error. you have to have cheat engine injected into the game for it to cause a vac ban.
Yes you can absolutely use cheat engine on steam and there is nothing to worry about. VAC bans are only a thing for valve games, and only apply for multiplayer.
No you won't get banned for having cheat engine installed. I won't go into detail, but most anti cheat systems work at a kernel level by preventing the game ...