Released in May of 2019, the Xbox One S All Digital Edition (model number 1681) is a revision to the Original Xbox One S (released in 2016). This model of Xbox One S ships with no Blu-Ray Disc Drive (thus there is no disc slit at the front), exclusively providing downloadable and streamable entertainment.
I don’t recommend water-cooling your Xbox as it can be a risk and it can be hard. The stock cooler already in it should be ok. If it’s overheating, try to clean it out, or re-apply the thermal paste. As far as I know, you will have to custom make your mount.