Fulcrum releses https://github.com/cculianu/Fulcrum/releases And this is an analysis made by Craig Raw, creator of Sparrow wallet, where he uses several electrum servers and Fulcrum gets the best results. It is from 2 years ago, but in the tests it wins by far. https://www.sparrowwallet.com/docs/server-performance.html

Electrs generally works well for personal use. It may be user wallets which are failing.