You have stated good types of investment plans for retirement but i do not find it convincing. Retirement plan means an installmental payment you make until you are out of work; which means bitcoins, bonds, or real estate is not a viable option except you earn so big. Why not just focus on saving monthly with banks? Do that for few months; then learn trading; perfect it, and do daily trading of lower percentages up until you retire.
i thought retirement plan is same as pension funds that only given to you once you are already retired . retired or not retired , the above list are not for everyone .
its okay if you dont find them attractive but to some that are looking for recomendations , that can be verry useful to jump start thier investing career here and outside crypto . saving money on banks is pretty basic and everyone will prioritize that before risking thier money to something that is uncertain