Dirt cheap Gigabyte B450 S2H is surprisingly capable of 3800 MHz RAM at 1900 FCLK (even official site only lists DDR4 3600 as a maximum supported frequency) : r/overclocking
PC Upgrade Kit AMD Ryzen 5 3600 MSI B450M-A PRO MAX - Upgrade bundles - LDLC 3-year warranty | Holy Moley