SideFX labs nodes are only available if I delete the Redshift related variables in my houdini.env

What can I do to circumvent this and have both SideFX Labs and Redshift work?

Sounds like your environment isn't configured correctly. Can you post the contents of it here?

Oh, it is working now, not sure what did it, sorry for wasting your time.

I'm sorry I guess the issue was not resolved.
I had created two houdini.env files, one for Redshift and one for Renderman, since I had problems getting them both to work.
And I must have confused them.

#
# NOTE: The use of packages is highly recommended instead of houdini.env
# See details about packages here: https://www.sidefx.com/docs/houdini19.5/ref/plugins.html [www.sidefx.com]
#
# Houdini Environment Settings
#
# The contents of this file are read into the environment
# at startup. They will override any existing entries in
# the environment.
#
# The syntax is one entry per line as follows:
# VAR = VALUE
#
# Values may be quoted
# VAR = "VALUE"
#
# Values may be empty
# VAR =
#

# Example:
#
# HOUDINI_NO_SPLASH = 1

HOUDINI_PATH = C:/CitySampleSource/Small_City/houdini;&

HOUDINI_USE_HFS_OCL = 0

HOUDINI_DSO_ERROR = 2

PATH = "C:/ProgramData/Redshift/bin;$PATH"
HOUDINI_PATH = "C:/ProgramData/Redshift/Plugins/Houdini/19.5.569;&"
PXR_PLUGINPATH_NAME = "C:/ProgramData/Redshift/Plugin/Solaris/19.5.569"
OCIO = "C:/ProgramData/redshift/Data/OCIO/config.ocio"

You can't create separate env files and use them at the same time... you have to either combine them into one file, or use packages (the recommended route).

The reason your env file isn't working is because you're defining HOUDINI_PATH twice, and not including $HOUDINI_PATH within the second definition (which would append any new paths to the original HOUDINI_PATH). Try something like this:

HOUDINI_PATH = "C:/CitySampleSource/Small_City/houdini"
HOUDINI_USE_HFS_OCL = 0
HOUDINI_DSO_ERROR = 2

PATH = "C:/ProgramData/Redshift/bin;$PATH"
HOUDINI_PATH = "$HOUDINI_PATH;C:/ProgramData/Redshift/Plugins/Houdini/19.5.569;&"
PXR_PLUGINPATH_NAME = "C:/ProgramData/Redshift/Plugin/Solaris/19.5.569"
OCIO = "C:/ProgramData/redshift/Data/OCIO/config.ocio"

Packages are a much better option once you get used to JSON syntax. Here's an article [www.toadstorm.com] about them.

To be clear, I only ever used one houdini.env at the same time, I just replaced it before opening Houdini.
For a short time period.
A silly approach nonetheless.

But thank you for correcting it and yes I should finally look into packages.

I have made two video tuts on how to install redshift and sidefx labs using the packages method, they work fine without any conflict. you can try them if you want.

@Mohanpugaz

Thank you, I had even followed both of these videos of yours before, but at some point I messed up my houdini.env which seems to have caused SideFX Labs nodes to not work.
Now, thanks to Henry Foster's fixing both Redshift and Labs seem to work fine.