For the Enterprise Service Desk,
ITSM "done right" is just table stakes.
20 years ago it was a big deal to have a feature-complete implementation of ITIL in some horribly heavy on-premise application. Pity if you wanted to upgrade that turnip.
These days everybody's SaaS and there are a lot of good ITSM implementations. To be honest, from where we sit, there is not much to differentiate between them except that the more recent ones usually work better and it kinda comes down to marketing budget.
ESM is harder though, and not many of these solutions were built with that in mind. ITSM is actually a subset of ESM, so if you want to go from ESM to ITSM you just need to implement a few business rules (ok, a lot of business rules), but if you want to go from ITSM to ESM you might just have to rebuild the product from scratch.
With that in mind, this video below gives a tour of Servicely's ITSM credentials, just so you know that those bases are covered.
Probably worth noting that in this video the AI Augment capability is switched off, so it's an apples-to-apples comparison with whatever ITIL tool you may be considering. AI gets switched on here.