At this point I suspect a controversial split will be the only way forward, keep in mind it only takes a very small minority of people to disagree to cause a split to happen in the first place. Which is definitely the case now, it is not unfair to think that some of these small blockist will simply never change their mind, and these two opposing ideologies can not exist on the same network since these differing visions also have very different road maps and projected outcomes for Bitcoin, which is why a split has most likely become inevitable.
You would be creating something that we've seen numerous times already, an altcoin. You can try to use pseudo-intellectual reasoning to justify that your split-off version is still Bitcoin, but it isn't. It's an altcoin per definition. Additionally, there have been quite some people telling you several times to fork-off already and re-brand yourself as whatever you want (to avoid general confusion that is detrimental to both sides).