I'd recommend Minetest+some full game instead of a reimplementation from an older version.
I know it's not the same; but some full games for Minetest are close enough and they will run on really old machines much faster than this reimplementation.
https://codeberg.org/mineclonia/mineclonia/pulls/3419 - Minecraft world gen (full reimplementation)
https://codeberg.org/mineclonia/mineclonia/pulls/3351 - raids
https://codeberg.org/mineclonia/mineclonia/pulls/2681 - much improved mob spawning
https://codeberg.org/mineclonia/mineclonia/pulls/2184 - a big mob rewrite
https://codeberg.org/mineclonia/mineclonia/pulls/2516 - client-side modding support, there's https://codeberg.org/halon/mcl_localplayer/ which makes physics and some other things way more Minecraft-like (elytras, proper eating, horses, etc), although currently it requires a Luanti fork since the upstream is not very interested in the changes.
Moreover, the "finitude" of the world can be mitigated by the fact that Luanti also offers 64 km total vertically out-of-the-box; various mods use this space to create the equivalent of "dimensions". In practice, without tools that allow to dig ridiculously fast, supposedly realistic mountains (what can be realistic in a game where you can carry with you several trees, casually jump 1 m anyway and barely get a scratch from a 15 m fall?), planes, dragons or whatnot, a "troposphere" of 1 km is plenty, and would allow 128 64x64 km "dimensions".
That being said, and my own biases put aside, people outside of the Luanti core team are working on that [1]
Among the various games that took inspiration from Minecraft (Voxelibre, Mineclonia, Repixture), some are more reliable than others. Those that don't try to be too close are the more reliable because replicating complexity tends to lead to more bugs.