You won't get it here. Everybody will recommend his favorite distro.
IMHO the best would be to solve your problems in OpenSUSE. This is definitely possible. You really need to switch to another distro only if you feel youself uncomfortable with the release cycle, package management tools or packages present in the repo of your current distro.
NB: global substitution s///g is not applicable here because you need to perform new substitutions in a substituted text. Both sed regexp syntaxes (basic and extended) don't support lookarounds that could solve this issue.
As I see, you've already got an answer how to convert text to lower case. So I just tell you how to replace all occurrences of %20 with -. You need to repeat substitution until no matches found. For such iteration you need to use branching to label. Below is sed script with comments.
sed
:subst # label
s/(\[[^]]+\]\([^)#]*#[^)]*)%20([^)]*\))/\1-\2/ # replace the first occurrence of `%20` in the URL fragment
t subst # go to the `subst` label if the substitution took place
However there are some cases when this script will fail, e. g. if there is an escaped ] character in the link text. You cannot avoid such mistakes using only simple regexps, you need a full featured markdown parser for this.
Yes. Just partition the drive manually, install packages with debootstrap, bind-mount /proc, /sys and /dev, chroot into it and install a bootloader. If you don't understand what I say, you have to run an installer, possibly in a VM.
If I'd decide to implement something like this, I'd consider two options: local repo with file:// scheme or custom apt-transport. HTTP server is needless here. (But I'll never do this because I prefer to rebuild packages myself if there's no repo for my distro.)
No, it is impossible to solve this on filesystem level. In theory, it would be possible to adopt some video codec for compression of such photo series, but it would be a lot of work to integrate it into immich.
Can you connect with
sftp?sftp myname@192.168.68.137