spawn eggs and spawners

in both of Java and bedrock there is a spawn egg to every entity in java they are very easy to obtain and to customise with command blocks unlike bedrock how ever that's not the biggest issue ,the biggest issue is that many the ones that are available don't work like item or area cloud or lightning(that used to work) spawn eggs and many of them don't work with spawners like the shulker bullet or wither head spawn eggs that used to work before.