Greetings swampmelon:
The short answer to your question is yes, following different "teks" does give you a rudimentary start to understand the principles of extraction and apply them to creating other herbal medicines...but, it is a little more complicated than that and you will probably have to put in a little more work and learning.
Most of the techniques used in extracting DMT can be applied to extractions involving alkaloids or any active substances that undergo solubility changes in different solvents according to changes in pH. Having said this, medicinal substances are not exclusively composed of alkaloids and so extracting them requires other principles and other techniques.
There are a few things to think about:
1) Many medicines do not need the level of purity that is applied to DMT (for the vapourisation route of administration). It is quite finicky to try and make medicines out of pure substances and powders; not to mention the amount of time and energy to go from a plant to a pure powder and then from a powder to another re-diluted form for effective dosage. Still using DMT as an example, it is quite possible to make a decoction of the necessary plants and still have an effective oral medicine without extracting to a pure powder. Also, many substances are actually quite poisonous and the danger of over-dosage increases in direct proportion to its purity.
2) If you have an holistic attitude to plants you may consider that the healing effect of a "medicine" many be due to more than just one chemical within it. In that case, a broader extraction path may be just as, or even more effective than exhaustive extraction to a pure substance. Decoctions, teas, oil extractions, tinctures and simple water extractions can be very effective and are less demanding on your technique and knowledge of chemistry.
3) Many medicinal plants are actually food or spices in their "natural" form. Incorporating them into your meals is probably the simplest "technique" to make use of them as medicine.
4) Essential oils can also be used as medicine. For most of us, extracting essential oils is not feasible due to the large amounts of starting materials required for extraction (like acres and acres of them) but they are available to be purchased and then used to make other formulations.
Making medicine is a huge field that ranges from the very technical (organic chemistry, pharmacy, etc.) to an art (herbalism, apothecary, etc). The "teks" you find on the Nexus are a very specific instance for a specific purpose originating from a much larger whole.
If you really have an interest in trying to apply the extraction arts to other medicinal plants you could possibly start by looking at some of the old herbals (like Culpepper) and look at what used to be done in the past with regards to formulations, dosage forms and preparations. Your next step after that is to get into a more serious study of organic chemistry. How far you go into it will be determined by your predilections towards "natural" vs science, the amount of time and effort you want to put into your endevours, the types of medicine you want to make and their final use.
I hope this helps you.
Happy extracting
Vi veri vniversvm vivvs vici.