I have both.
A 2017 Smuggler with a coil shock, Stan’s Flows and a more ‘trail’ build. And a 2019 Sentinel, in alloy, with a full heavy build, 4 pots, inserts and heavy tyres. Got the Sentinel for racing, uplifts and bigger rocky days. Tend to use the Smuggler for day to day riding and the Sentinel if I’m away for a weekend. Live in Notts, so tend to ride Derbyshire/Peaks regularly and I’d use the Smuggler for that.
I’m in a similar issue, there’s fairly significant overlap in them both, but I find the Smuggler more engaging to ride on tamer terrain than the Sentinel, and more suited to longer days in the saddle.
With the second hand market as it is at the moment, o should probably sell them both and build up a new Sentinel to do it all!