It’s always good when asking questions here to give context. How much knowledge, experience, skill, budget, etc do you have to apply? What are the objectives, short term and long term? Test Equipment is like a tool - it can help a person solve problems, learn, and have a very enjoyable journey - but it can sometimes be like a drill to make rabbit holes.
The question about a “reasonable investment” is a good one - but give some thought to that not just for a power supply or two, but for a bench full of test equipment that might surprising populate like rabbits. There are threads here you can find by searching that give advice on what new enthusiasts should consider with respect to various types of test equipment, tools, parts, consumables, etc.
The forum members here are super helpful and will try to answer your questions but you will get the best answers when you frame the questions well with your context. Otherwise you might get a lot of enthusiastic answers from someone else’s context. Checkout a thread called “TEA”; there might be at least a couple - one short and one long. If you read thoroughly you might find, for example, some people will say you haven’t reached par on oscilloscopes until you have 19.
After ~10 years of thoroughly enjoying EEVblog I’m about 15 short of par on oscilloscopes but I’ve made due with just (2) Korad power supplies. That doesn’t mean Korads are right for you - but I’m sure a person can learn a lot and get a lot done with <30 volts and <5 amps if the PS is easy to use, reliable, and accurate to a few hundredths of a volt and a few milliamperes - which the KA3005D is. It will probably be fine out of the box but there is a calibration routine you can use to dial it in with a DMM. But here you see the beginning of the rabbit hole. What if your DMM isn’t accurate?
My suggestion would be start with a Korad PS and a couple decent DMMs (so you can measure voltage current at the same time), and climb in the rabbit hole.
Once you see voltage and current on your two DMMs agree with the voltage and current readouts on the Korad and all four readouts agree with the calculations you made before hand for your Device Under Test you will be certified to climb in and out of the rabbit hole under your own power - just watch out for TEA symptoms.