I just migrated from Claude. What am I doing wrong?

So it was already really difficult for me to keep using Claude with its limits. I was really tempted by Codex also because it's in the weekend where I do most of my work and the 5 hour window is really inconvenient for that. Thing is, I'm finding it really really difficult for codex to understand basic stuff that is either explained on docs (that according to the migration process, were migrated) or its just too basic, like "change a and b, changes a alone, ask to change b and it reverts a). Are session windows different from the ones in Claude? Am I missing something on that migration? I'm using Sol on high to plan and Terra on high to execute. Thanks