You bought the 5800h last year, and provided last year's price paid for it. That makes the 2024 Mac mini more relevant than the models that weren't being made or sold last year. Unless you'd like to dig up what that 5800h system cost back in 2021, to put that into context against a Mac mini from back then?
The Beelink mini PC I bought MSRPs at $600, but it comes with a 500GB NVMe drive. In Apple's pricing scheme, that puts it equivalent to a $800 Mac Mini configuration.
To reiterate, this is absolutely a comparable machine to the Mac Mini in terms of performance. Maybe not your ideal configuration, but I had $300 and a limited patience for Asahi development.