Read/write split vs. weight in Proxysql

Is setting the same weight for readers the same as making rules for reads to go to nodes configured as readers in Proxysql?

Right now I have one PXC node that gets all writes and reads because of higher weight as both writer and reader. Will the same weight on all reader nodes make Proxysql load balance between reader nodes?

You probably have one node getting everything because you’ve configured it as the default hostgroup. If you want to split reads/writes, you will need to create 2 rules: 1) ^SELECT.*FOR UPDATE and 2) ^SELECT both of those rules should have a hostgroup destination for your reader pool. Within your reader pool, you should only have readers with equal weights.
You should be using the mysql_galera_hostgroups table too in ProxySQL, which will manage writer/reader pool membership based on galera status of each node.