concaveman | A very fast 2D concave hull algorithm | 3D Animation library

I have a script using the R package 'concaveman', but due to issues on the ubuntu platform that I need to run the code on I cannot install this package (it has taken me three days trying to solve it). So I am looking for an alternative.

I have a random set of points ranging from 3 to 1000s of points. I want to draw a convex hull/polygon around the outer most points (step after would be to rasterize). I have been trying to do it by converting the points to a raster, then use rastertopolygons, but in rare occasions points would be in the same raster cell resulting in only two unique points. Convaveman would make this into a linear polygon (which is what I want, without using concaveman). Here is the input data that would be problematic:

Data: In the data below I have clusters, which are 2 large groupings of the data. Within each cluster are 5 districts. I use the points within each cluster to create a polygon for the cluster.

Problem: I'm attempting to calculate voronoi for each district within each cluster. So each of the 2 cluster polygons should have 5 voronoi cells within it. How can I create 5 voronoi cells bounded by each cluster polygon?

edit: This question has now been correctly answered here: https://gis.stackexchange.com/a/378085/171458

I have a shapefile consisting of 262 rows of MULTILINESTRINGs. Combined this shapefile (the political boundary of the arctic region) wraps the world and I would like to check for a large set of coordinates if they fall within this shapefile. I know how to do that, but that does require having a closed polygon, instead of a combination of lines. Some of my solutions have come pretty far, but none actually work.

I have looked at this: https://gis.stackexchange.com/questions/290170/convert-a-linestring-into-a-closed-polygon-when-the-points-are-not-in-order and this page: https://gis.stackexchange.com/questions/332427/converting-points-to-polygons-by-group

The shapefile can be downloaded here: https://www.amap.no/work-area/document/868

I have also posted it here: https://gis.stackexchange.com/questions/378010/combining-a-feature-collection-of-multilinestrings-into-one-closed-polygon-in-r, but I am also asking it here because I only have R available for this task.

I have point cloud data of an area (x,y,z coordinates) The plot of X and Y looks like:

I am trying to get polygons of different clusters in this data. I tried the following: