When I run the mod and maraxsis with version v2.1 of the game, the game gives the following error:

Failed to load mods: __science-tab__/compat/maraxsis.lua:9: attempt to index field 'maraxsis-fill-research-vessel' (a nil value)
stack traceback:
__science-tab__/compat/maraxsis.lua:9: in main chunk
[C]: in function 'require'
__science-tab__/data-final-fixes.lua:9: in main chunk 

It seems maraxsis-fill-research-vessel has been removed by the newer version of maraxsis.

According to maraxsis's changelog, the research vessel was removed in the changes for v1.34.1.

I'm checking this now.

Thank you for your effort — I updated and tried again, and everything works normally now.

That compat will also move into maraxsis at some point.