I own a Corolla of similar vintage and always wondered the options available if ECM fails. So I’ll be carefully following what happens on this thread, hope you will keep us informed. I think my first choice would be to purchase a used ECM obtained from the same make/model/year/configuration as my own car, from a wrecked car, car parts recycler, pick and pull, etc. If nothing available, then I’d try the companies that rebuild them. fyi Summit Racing’s website sources replacement ecms for some cars. One problem you’ll have though is your make/model is probably not as widely sold as say a toyota pickup.
Note: One caution, if your state requires emissions testing, that may throw a monkey wrench into any replacement plan b/c while replacement ECM may work ok, it may not produce the required emissions levels.