Typing Engine's approach — analyzing the client's actual brief for keywords and requirements rather than filling in a fixed template — is exactly the right instinct for this task, and it's the same core mechanic SMBkits' freelance proposal generator uses: the job posting and your background go in, and a proposal referencing the specific ask comes out.
The reason this matters is what clients actually do when reading proposals: they skim dozens of near-identical submissions on a listing, and a generic opener that could apply to any job is usually the first thing that gets them to stop reading. Referencing a specific detail from the posting — the exact task, a tool they mentioned, their stated deadline — in the first sentence signals the proposal was written for this job, which does more for the reply rate than a longer list of credentials further down.
Length matters as much as relevance. A few sentences that reference the specific job and state clearly how you'd approach it consistently outperform a long proposal, since clients rarely read past the first few lines of a freelance bid tool's output regardless of how well-written the rest is.
Both tools solve the same core problem the same way — free, no daily credit cap, no account required for the core generator. Treat either output as a strong first draft: add one detail only you'd know, a specific past project or a question about their timeline, before submitting.