You can generally resolve it yourself by poking seldom used functions to keep them hot. But no, they haven’t provided a solution to cold start (unless you consider ec2 or fargate a solution).
We've tried this and it helps somewhat but when AWS attempts to scale your function based on load, cold starts re-appear. We've moved away from Lambdas where a dependable response time is required.
If you are experiencing cold starts it means that function is not used very often. If it's not used very often that likely means it's not user facing (or something less important like a Terms of Service page). If that's the case, why do you need instant response times?
With delays as bad as 8+ seconds for ENI attachment, this is a significant holdback (https://medium.freecodecamp.org/lambda-vpc-cold-starts-a-lat...)