It can often improve performance and memory latency and usually only has a minor CPU performance impact as it trades cycles waiting for memory for cycles decompressing memory. It is usually decent even on low power embedded devices.
There are a few edge cases where ZRam is not great. If your data is already compressed or encrypted copying it around in memory is much more expensive. It’s also harder to tell exactly how much data can be loaded into the “free” memory. It’s also a bit slower for serialized memory access in large data sets if the compression ratio is low.
It looks like underextrusion at speed. It might be a clog or you might want to try a higher hotend temperature. PLA can have inconsistent ideal temperatures even with the same brand due to different colors and additives between batches and 185 is on the low side.