the character set named as speccy.char is from zx80 and zx81, not zx-spectrum - zx-spectrum is ascii7 based (undercase and everything)
Thanks for pointing this out, that character set image is from 8 years ago and I just never checked it. The next release will have an updated version that properly reflects the Spectrum character set, in the meantime you can download the two files here:
https://heptapod.host/jp-lebreton/playscii/-/commit/1bfc3f60f3b91a9f41d13fefaa14...