confiture.nvim VS exrc.vim

This is also not a direct response to your question as I'm not familiar with asycntasks.nvim, but having a build and run functionality is probably the main reason why I wrote confiture.nvim, which is another task launcher plugin (that also aims at being simpler than overseer). The main limitation with the implementation of the build and run of confiture is that the build phase will not be asynchronous. It is sufficient for my workflow though -- if I know the build command will be long, I usually launch it on its own first, which can be asynchronous using confiture (with vim-dispatch under the hood).

It's can also be used from vim to launch custom commands (as is done for example in my other plugin confiture.nvim)

It doesn't answer your question but this is how I do what you described : https://github.com/romainchapou/confiture.nvim

I'm mostly fine with language specific configuration, which I find not too hard to manage in my init.vim, but I rely a lot on project specific commands for building and running projects, so I'll do a shameless plug for my plugin, confiture.nvim, which aims to provide a simple solution for this.

exrc can enable untrusted arbitrary execution. See https://github.com/ii14/exrc.vim that tries to mitigate this.

'exrc' option or https://github.com/ii14/exrc.vim

Yeah, here's my plugin that does that: https://github.com/ii14/exrc.vim

:set exrc and and create .exrc file in your project directory with your project settings, or use a plugin like https://github.com/ii14/exrc.vim or https://github.com/jenterkin/vim-autosource

I did basically the same thing, but without recursive lookup: https://github.com/ii14/exrc.vim

https://github.com/ii14/exrc.vim for local vimrc. Basically a reimplementation of the 'exrc' option that keeps track of file hashes, so you don't evaluate anything malicious, without the limitations of 'secure' option.