I've long thought that the time lag/hysteresis for a system as large as the earth has to be many decades, or even centuries. So once you see it start to move, you ain't going to stop it, not reasonably, in any short time.
So, yes, a degree of heating is inevitable. How much, I don't know. How long will it take to stop it? - again I don't know, but it will be decades, if not centuries.
The minute we stabilise emissions at net zero, we stop increasing the heat content of the earth, and climate settles down within 30 years, as long as we don't hit any tipping points. The minute we switch to net carbon negative, we start shortening that 30 years.
Every pound we spend now on mitigation, will save several pounds on adaptation in the future. And that applies up to very high levels of intervention: so we could globally shoot for net zero within 25 years, technically we could achieve it, and economically it saves us much more than it costs us.