On my C456 hardtail – Bash ring on one side and an n-gear Jump Stop on the other. That combined with a short cage X9 mech and chain length set for a hard tail. Oh and a proper single ring is essential. I use an FSA Single DH ring which is much better at keeping the chain on.
Works pretty well, though the Jump Stop is just attached to the seat tube and slips round sometimes even though it’s done up very tight. Mainly if there’s a chain suck incident and something pops off somewhere and jams, but not sure what/how it does it. Rare though.
Next up is my full sus converting to 1×10, but for that I’ve got an e.13 TRS+ which is a lightweight Trail/AM guide with top guide and bottom roller. After the hassles I’ve had with it in 2×10 set up (X0) and chain jump/drop loads without a guide, and additionally still hassle with an MRP X-Guide which just has a bottom guide, not top, then the number one priority really I feel is something to keep the chain on at the top and as much tension in the chain that you can get away with safely. Bear in mind you need to account for the rear suspension with a full sus and the chain will be naturally slacker than on a hard tail at times.