justRTP

[1] The safe-location search is a lot faster now, especially the first teleport into unexplored terrain. Every attempt used to generate a nine-chunk block and wait a couple of ticks, and its height lookup could stall the main thread loading a chunk it had already loaded. Now each attempt loads only the one chunk it checks and reads the height straight from it, so a search that took a few seconds lands in well under a second. This covers custom-radius teleports too. Ocean and lava spots are still rejected exactly as before.

[2] Custom-radius teleports use the cache now. A /rtp used to skip the ready-location cache and always search live. If a cached spot happens to fall inside the radius you asked for it is served instantly, otherwise it falls through to the faster live search. There is a switch for it, location_cache.serve_custom_radius, on by default.

[3] Fixed high overworld ground being thrown away. A leftover height cap rejected any spot at or above Y127 and even logged a scary "nether ceiling" error for it, so on 1.18+ terrain every hill and mountain wasted attempts and a mountainous area could fail outright. The overworld now uses the world's real build height, so you can land on a peak like anywhere else, and the false error is gone.

[4] The Nether and End use their own attempt counts again. Queued teleports read the wrong setting and always used the overworld number, so attempts_nether and attempts_end were quietly ignored on that path. They apply now, so sparse dimensions get the extra tries you configured.

[5] Pre-gen harvesting is gentler on the server. It pauses whenever TPS drops below the pre-gen floor, and the default cap is lower (the cache only needs a few dozen ready spots, not a couple hundred), so filling the cache while a pre-gen runs no longer piles chunk generation on top of chunk generation and drags TPS down. If your config still shows the old high cap you can lower pregen.harvest_max_per_world, but the TPS backoff already keeps it in check.

[6] Hardened the block blacklist. It accepts namespaced ids like minecraft:water as well as plain names, works on any server language, and quietly skips a bad entry instead of letting it get in the way.

[7] Steadier config and world handling. Merged config updates now apply on the very first start after an upgrade instead of needing a second restart, tested upgrading from 3.5.9 with your own values kept and the old file backed up. Worlds loaded after startup, for example by Multiverse, get their cache prepared without resetting everything else, and the background cache filler can no longer pile up duplicate workers or get stuck on a world.

Note on radius: /rtp places you that far from the centre as a straight-line distance, so a coordinate like -2641 can still be 5842 blocks out and correctly inside a 5000 to 6000 request. Only the SQUARE shape reaches into its corners past the max, which is by design.