Alternative to manifest v3 chromium extension

Question

Currently, I have developed an extension that handles a web page for 24 hours, basically an automation for a browser. But the problem I'm facing, is that the released manifest v3 doesn't allow it to work for more than 2 hours without stopping (currently, the "service work" of any manifest v3 extension works for only 5 minutes, but an open tab works for 2 hours until the entire browser crashes). I've already tried a manifest v2 extension, but the large structure of my code didn't pay off, I've already tried to create an automation using Python 3, but it didn't have much compatibility with slow computers, so in the end my client didn't like it and failed the project. Any solution? to "inject" javascript to automate a single web page for a long time, it can be per app or not, but I need ideas!