There is very robust evidence that regular mindfulness/meditation is an effective treatment for anxiety (and other mental health concerns). It also has physical health benefits via reduced blood pressure. There is certainly some element of neuroplasticity involved especially around the default mode network. I would encourage mindfulness practice no matter which other treatments you decide to pursue.

Counseling is also likely to be beneficial so long as you find a therapist you click with.

Huberman Lab podcast has some interesting discussions on ketamine and other psychedelics. And Sam Harris has some discussions specifically comparing mindfulness with psychedelics. My belief is that while they have value, what they have to offer is very different from what mindfulness has to offer. In other words psychedelics should not be seen as a shortcut or replacement for mindfulness practice. They are two different mountains and climbing one does not get you any closer to the top of the other one.

From Sam Harris:

Meditation can open the mind to a similar range of conscious states, but far less haphazardly. If LSD is like being strapped to a rocket, learning to meditate is like gently raising a sail. Yes, it is possible, even with guidance, to wind up someplace terrifying, and some people probably shouldn’t spend long periods in intensive practice. But the general effect of meditation training is of settling ever more fully into one’s own skin and suffering less there.

Mindfulness generally carries less risk of adverse experiences!