Hi João,
I found a solution to the columnized text in the slime.html file. Rather than using:
texi2html $<
in the make file, I used:
makeinfo --html --no-split $<
which works just as well, but without the single-columned text.
If you find this acceptable, I've attached the modified makefile from slime/doc to this message. I don't know how that might impact other users...
The version of texi2html that is available on my Linux Mint is version 1.82-ubuntu. I did some searching and discovered that there is a version 5.0 available, but not on my distro. I was hesitant to install it because it might break something else.
By the way, slime-mrepl seems to be usable for my purposes. At first I thought it wasn't working until I stopped redirecting all the output to the main repl. then it started responding properly.
Thanks,
Paul Bowyer