After the pandemic, the "25$" SBC suddenly became 100+ with low availability. The main thing that made rpis worth it is gone now, and they're all chasing number go up on benchmarks.
However, SD Cards are really terrible devices to run a general purpose computer on and they are designed for storing large files like photos, videos and mp3’s sequentially not the SWAP, logs, and databases that a full operating system is constantly writing and accessing in a random fashion.
I think if you are running a base 2gb, then maybe absolute value makes sense, but once you start hitting the larger RAM configutations, an M2 slot is a no brainer.
I think the cheapest working SBC is really the zero line.