For local chat Jan seems okay, or OpenWebUI for something hosted. For IDE integrations some people enjoy Cline a bunch but RooCode also allows you to have multiple roles (like ask/code/debug/architect with different permissions e.g. no file changes with ask) and also preconfigured profiles for the various providers and models, so you can switch with a dropdown, even in the middle of a chat. There’s also an Orchestrator mode so I can use something smart for splitting up tasks into smaller chunks and a dumber but cheaper model for the execution. Aside from that, most of the APIs there seem OpenAI conformant so switching isn’t that conceptually difficult. Also if you wanna try a lot of different models you can try OpenRouter.
Something like opencode probably, that’s what I have been using to freely and very easily switch between models and keep all my same workflows. It’s phenomenal really