Can you not choose from multiple models in Copilot? My understanding is you can.
For completion models: no, they retired gpt-35-codex, leaving only 4o-copilot.
From my experience (GH Copilot Pro with engaged_oss SKU, ie. for free), after they announced their "pricing changes", they also made the performance worse. The completions went from good, to actively distracting. tldr; they enshittified it / did a rugpull.
Right now, it is not worth paying for. ChatGPT Plus is far better value for money if you don't care about autocompletions/pure vibe coding.