ECM/Key fobs: 2014 Chevy Cruze 1.4L turbocharged 4-cylinder

Hello all! About 2 months ago my car stopped working in a McDonald’s drive thru (that was fun!). My husband and a Good Samaritan pushed it into a parking spot and then after a few attempts, my car actually did start. I was able to drive it the 3 ish miles home but it was like my car didn’t know it was working? It wouldn’t tell me the miles per hour I was going, the RPM, didn’t want to shift gears, etc. but I did make it home.

We got someone to scan it and one of the codes indicated the ECM might have been messed up. My dad bought a used ECM and put it on my car and when trying to start it, I was getting a theft detection activated alert or something along those lines - I know it was theft something but don’t remember the exact phrasing.

That was about a month ago. I really need my car fixed but this car has had soooo many problems and isn’t worth much so we’ve been debating on how much we are willing to spend to get it fixed and local places have told us a huge range in pricing since it’s not really known what’s needed. We aren’t sure if the ECM itself needs to be programmed (it was from a totaled vehicle but is the correct ECM for my vehicle).

One of the local shops told us that I’d need two key fobs. I only have one key fob and the buttons don’t work. When I was looking into getting some key fobs, I stumbled upon some info making it seem like the key fob itself could be the only issue and if the key fob was programmed, the car might work again. The article made it seem like the key might be preventing it from starting due to the theft protection only.

A local locksmith was recommended to me and he will come to my house and program two keys to my car. Would this be worth trying or is there no way the key fob is the only issue?

I don’t have all the codes handy but can get them from my FIL if needed.

Thank you in advance for any and all help!