Those who have spend time in Bitcoin have consent that it's ideal to invest into Bitcoin for long term. But that's not the case with new comers, most of them came with mind that Bitcoin is about getting rich overnight and when that desire is not fulfilled they get disappointed.
Regarding three techniques i.e. Lump Sum, Buy the dip and DCA, anyone with experience can adjust buy the dip and Lump Sum with DCA. If I am a new comer, I would prefer to go with small amount i.e. investing small amount every week or month. Once your confidence is developed you can go for Lump Sum with some increased capital. Both DCA and Lump Sum are good as long as you are confident about the technique you are adopting.
I think there are only two method that I know of which is lump sum buy and the DCA method. You mentioned buying the dip but this is also a lump sum buy that is done when price retraces after an upward movement. It is different from buying using the DCA method because it involves an instant order whereas the DCA is a continuous buying process that is done weekly or monthly as the case may be. Maybe there is further distinction between between buying the dips and other forms of buying that is done at once for which I consider less important so as to avoid memorizing too many things. Maybe for academic purposes, such distinction might even become necessary and there is nothing wrong about it.
A combination of both methods is possible but it requires someone with experience and discipline to do effectively. I will not recommend that for a newbie to avoid being emotional about the whole process, rather I will suggest focusing mainly on the DCA method that is easier to follow and produces outstanding results when followed dutifully. However, no matter what method is adopted, some level of effort is needed to be able to follow such method with a sense of responsibility.
There are many methods or strategies to build your investment portfolio well, one of which is being discussed is buy dip and hold. It is recommended that DCA be carried out on an ongoing basis so that your average costs are lower compared to buying a lump sum. Both methods are not wrong, you can combine them with whatever approach you think suits your financial situation.
You don't need to be a professional to invest. What you need is capital and courage. You have to understand what the risk is and how to minimize it, even if you are not very good at making analysis, you can still generate returns just by buying and holding. Buy with the DCA method and hold can help you get a low average price, regardless of your entry price.