Long-term Bitcoin holding always gives people the greatest chance of success, so investing according to a 5 to 10 year plan will give you a very good chance of success, but to sustain this investment in the long term, people will always have to face difficult situations, so it should never be seen as easy, it is more difficult than people expect, especially for those who decide to invest in Bitcoin without any emergency fund due to their self-confidence, this can really lead to a terrible situation, and this is why it is essential to prepare an emergency fund if you want to hold Bitcoin effectively in the long term, having an emergency fund reduces the mental stress in investing a lot, because you do not have to sell Bitcoin suddenly, and as a result, no matter what situation arises, your Bitcoin investment will not be threatened in any way.
Easier said than done, we first have to generate money that goes into emergency funds. If you are doing job only then your salary will be used for daily living while with discretionary income one can generate emergency funds and also allocate capital for Bitcoin investment. The discretionary income will kill two birds with one stone i.e. it will give you emergency funds that gives you peace of mind that you have money to deal with any situation and it will also help you in accumulating Bitcoins that you can retain for 5 years or more.
You are right about long term holding, the issue is cash flow always. It is almost impossible to save an emergency fund and a Bitcoin position without discretionary income. Overcommitted early investors without a buffer like that tend to panic-sell during dips and lose year-long gains. The easiest way will be to initially fund 3-6 months of expenses and then progressively invest remaining discretionary funds in Bitcoin. I believe that patience and planning are more important than hurry to purchase.