No, they conflict with each other by design. See the relevant PKGBUILD's in our Gitlab below (see "conflicts"):
But you can swtich between the two easily with the Garuda Assistant.
This is not clear: it is your system, so you can install a different Desktop Environment in your system, but this is risky/complex, requires knowledge, so this would make your system an hybrid and not officially supported (please mention this change, if you'll go on with it, in your next topics).
If you meant if you can install more than one Garuda Edition on your machine, this is also possible, and many of us do it, but also multibooting is not officially supported.
It might require some attention to have two or more EFI boot entries, but it is not complex.
Anyway, please, one topic per topic.
Actually, the purpose of the power saving tweaks is to reduce the power consumption by compromising the performance.
On the other hand, Performance tweaks runs the CPU on the maximum required frequency to achieve maximum responsiveness and best performance.
But power saving tweaks are actually fully optimized too, as compared to other proprietary OS. That is, your system will still perform reasonably good, and won't let you down.
Its just that you can switch to performance mode if you want to squeeze out the best performance of your computer, No matter the power usage.
I guess I am clear enough.
Certainly you can, I indeed had multiple desktop environments on a single installation.
But you must know what you are doing and how things work to actually maintain them together. If you wanna experiment, go ahead, but keep in mind that it is not supported.
So, if you install multiple Desktop Environments and that causes any troubles for you, the forum admins may simply not address the issue at all.
Certainly, it is fun to experiment. After all this is Linux. But along with experimentation comes the necessity of cleaning up one's own mess when said experiment(s) don't provide the hoped-for results.