rely is comparable to khatru, so it's a framework to build your custom relay. Pyramid is a specific relay built on top of khatru I suppose.
Building your own relay is quite easy and doesn't take much...
I've made a basic start: https://rely.nyves.nl/
Source: https://github.com/nostrver-se/rely/tree/rely.nyves.nl & https://github.com/nostrver-se/rely/blob/rely.nyves.nl/relay/rely_nyves.go
The todo's / requirements: https://github.com/nostrver-se/rely/tree/rely.nyves.nl#nyves-relay-features
I also made a repo of the current pyramid relay with the migration scripts (all vibe coded) which can be found there: https://gitworkshop.dev/relay.nyves.nl/relay.ngit.dev/relay-nyves-nl/tree/relay.nyves.nl/nyves-migration/broadcast_unified_streaming.py
Source: https://github.com/nostrver-se/rely/tree/rely.nyves.nl & https://github.com/nostrver-se/rely/blob/rely.nyves.nl/relay/rely_nyves.go
The todo's / requirements: https://github.com/nostrver-se/rely/tree/rely.nyves.nl#nyves-relay-features
I also made a repo of the current pyramid relay with the migration scripts (all vibe coded) which can be found there: https://gitworkshop.dev/relay.nyves.nl/relay.ngit.dev/relay-nyves-nl/tree/relay.nyves.nl/nyves-migration/broadcast_unified_streaming.py