Hey @luc_Dev - on my side of things I can’t speak too much to 3P integrations, but wanted to reply here to see if I can help out.
Right now, our current API direction is GraphQL-first, with the REST Admin API now considered legacy. For our GraphQL workflows, the versioned schema is the contract: @shopify/api-codegen-preset can validate operations and generate types, GraphiQL supports interactive testing, and Shopify CLI now provides shopify app execute and shopify app bulk execute for scripting and automation.
If the OpenAPI specifications describe services owned by your team, that’s a separate toolchain and Shopify doesn’t prescribe a particular Redocly replacement. Could you clarify which Shopify API surface you’re integrating with and what specific limitation is prompting the move away from Redocly? That would make the comparison a bit more concrete and I can maybe point you in the right direction here.