Howdy howdy, bit of an odd question for you.
I grafted together a 2.1 version of metal and stars for personal use.
However this mod, in conjunction with outer rim and redrawn space connections/compatibility, severs the connection between the Calidus and Senestella stargates.
Any way I can manually connect the two points myself?
Apologies if this isn't the correct place to ask.

Wherever the route is defined in your Metal and Stars fork, add redrawn_connections_keep = true to its definition

So something like:

data:extend({{
    name = "calidus-senestella-stargate",  -- or whatever it's called internally
    type = "space-connection",
    ... -- other things like asteroids and length, etc
    redrawn_connections_keep = true,
}})

Ah gotcha gotcha.
Highly appreciated, fella.

If that doesn't work (which I just realized, it might not, because the naming pattern is slightly different than expected), then I might want to see the log, specifically to check if it's RSCompat or BAB removing the connection.

I wanna say it's BAB (which prunes any connections crossing the belt, unless they include the name 'stargate', and I think Metal and Stars just calls them 'gate') since it actually ignores the redrawn_connections_keep variable (just in case those happen to cross the belt, and weren't intended to preserve a belt-crossing connection).

I implemented a version of that variable for both RSCompat and BAB, just in case (but for this case, I'll probably just want to change the check from 'stargate' to 'gate')

Apologies about the delay, got a tad busy.
Did some poking around and I found this line specifically:
17.045 Script @kry-asteroid-belt/lib/asteroid-belt.lua:300: Removing connection crossing asteroid belt: stargate-connection-calidus-senestella

I can post the whole thing if you still need it, just need to know where I can do so.

I had a feeling that's what was happening, looks like Metal and Stars refers to those two connection points as 'gate' internally, not 'stargate', so I made the name check a little more lenient so it applies to just 'gate' as well.

Fixed in v1.0.6

Works like a charm. Christ man, I cannot thank you enough.