Not free, but based on Ardour is Mixbus by Harrison (standard or 32c). Not sure about Ardour, but Mixbus does a system check and configuration for you automatically on install. All you need to do is install the -lowlatency kernel if you require additional low latency performance/reliability. Not needed for printing VIs but IMO necessary for audio recording. Jackd is not required, as Ardour/Mixbus can grab hold of the sound card directly via ALSA. You only really need Jack if you plan on multiplexing audio from various sound sources. If you are OK with the DAW monopolizing the sound card temporarily and don't need to connect and route audio between various software, then don't worry about it too much. Monolithic DAWs such as Ardour and Mixbus and Reaper can handle everything internally, which makes jackd somewhat superfluous.
Mixbus provides a bunch of great plugins that are pretty cost-effective, and you can also check out the EQ10Q and Calf Studio Plugins packs, for example, for some really nice free options.
Biggest issues with configuration:
- Set CPU governor to "performance" or otherwise disable frequency
- Disable or pause background processes that may hog precious CPU cycles (indexers, performance monitors, fancy graphics, system
updates, email/IM feeds, networking, etc)
- Use a lowlatency kernel with RTIRQ (the RTIRQ version in the repositories may be very outdated, I think .debian repos still have a version from 2015!)
- Add your user to the @audio group
- Configure your /etc/limits.conf file for realtime audio
You can google these things to find more detailed discussion about them.