A freeze that hits right as the terrain starts loading on join is usually memory: joining a busy server spikes RAM usage, and if the allocation or your total system RAM is too low the game becomes unresponsive. Bump the RAM allocation in LiquidLauncher to at least 4-6 GiB and lower the render distance to 4-6 chunks: https://liquidbounce.net/docs/tutorials/fixing-fps
If it still hangs, paste the end of latest.log to https://paste.ccbluex.net and send the link β a "not responding" during world load usually leaves a trace there. Also let me know whether it happens on every server or just one.
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