Supports Liquid and Nunjucks for templates and Markdown for posts, and YML, JS and JSON for data. Produces an optimised website as the output.
My own site, which has about 84 pages takes under a second to start a development server and about 40 seconds to run a production build(asset minification and versioning, HTML minification, inlining critical CSS, sitemap generation, etc.).
Do take a look!
Hugo - Pretty much the same issues with Jekyll and Pelican, and the templating language also leaves a lot to be desired. If build speed is paramount to you, choose this.
11ty - I just benchmarked lego against this and it looks like there is only a couple ms difference performance wise. The only real difference is that 11ty lets the users configure everything and decide what kind of optimisations they want(or if at all they want it).
lego supports the templating languages of both Pelican and Jekyll and is reasonably fast as well. It also optimises the output build as much as possible. If at all you decide to use it, please share your feedback.
Another important factor, in your case, might be the availability of templates. Pelican, Hugo and Jekyll should have readymade templates for most use cases and should save you time spent on designing the layouts, writing CSS, etc. I am not sure if 11ty has such an ecosystem. lego definitely doesn't have any templates and you might want to factor that in your decision.
I hope this answers your question. Also, all the best with your dissertation :)