It helped a bit restoring the phone and creating a new backup to restore from beforehand.Using the device over the last week I've surprisingly seen an improvement. It's not a massive change but it gets me through 3/4 of the day rather than just 1/5 compared the before!
It still gets hot. Haven't facetimed, but it's still a very warm phone. Battery got a bit better in terms of it's life, maybe a tad worse on 11.2.2. Hopefully 11.2.5/11.3 changes things.