Yeah, he preached against indulgences (I doubt he’d approve of the certificates of absolution sold by the Ecumenical Patriarch and Jerusalem Patriarch) or churches having fees for sacraments like baptism. Also he promoted women preaching in church services and promoted Wycliffe’s (An English proto-Protestant who opposed iconodulia, invocation of the saints, the real presence of the Eucharist, and the efficacy of sacraments) materials both by translating them into Czech and in some cases reading them out verbatim. I really don’t get why he’s venerated when he was never part of the Church, promoted a figure who the Orthodox would consider heretical, and who’s followers joined Luther’s Reformation. I guess because of Czech nationalism and his anti Latin stance he is venerated amongst the Czechs, but I don’t think those are good reasons to establish veneration towards him.