opi VS openSUSE-release-tools

This is incorrect. It also installs a set list of packages.

Have you looked into OPI? This allows you to easily search and install community packages from the Open Build System similarly to how it is with working with yay on Arch. It very likely does not contain things like git packages or fonts but it can be pretty useful for packages like ckb-next and since it pulls from the OBS it is always guaranteed to be a binary, no compilation necessary

As of this writing, opi performs the following operations behind the curtains (see here for reference):

opi will implement a workaround in https://github.com/openSUSE/opi/pull/120 which will force the ffmpeg version on tumbleweed to be >=5.

OPI is your friend. You don't have to update every day...once a week or so is fine. Set up multiversion for kernels. A lot of times if a vendor offers a Fedora RPM and not openSUSE, the Fedora RPM will work fine. If you are using Nvidia, wait to update kernels... that's all I can think of. Use and update the wiki as needed, it's a good resource, but can get outdated.

Yeah I'm pretty sure it's using Packman https://github.com/openSUSE/opi

For more information https://github.com/openSUSE/opi

OPI is also useful for finding other packages that aren't in the regular repos

The easiest way to install software is with OPI, you can also search with Zypper or YaST. Generally, if you can find an RPM file built for Fedora, you can install it on Tumbleweed as well - I'm sure there are exceptions.

Or are you trying to put software already on the OBS through openQA before distribution? Yes, this is done by the Tumbleweed deployment scripts which are in https://github.com/openSUSE/openSUSE-release-tools